p.md

P

PaaS : → Platform as a Service

package.json : A file containing dependencies, scripts, and metadata for npm (Node Package Manager) or Yarn packages.

package-lock.json : A file that describes the dependencies and the exact tree that were generated for an npm package so that an identical tree can be recreated, independent of interim dependency updates. package-lock.json is intended to be committed to version control.

Packaged Offline/Online Webpage : The use of the PNG image format to store a ZIP archive of a website in a PNG image’s metadata. ℹ︎ hi.pow.tools

Packed : A property of an array that consists only of elements (no holes), and that can be optimized accordingly.

Packet : A formatted unit of data carried by a packet-switched network. A packet consists of control information and user data, which is also known as the payload. Control information provides data for delivering the payload, for example, source and destination network addresses, error detection codes, and sequencing information. Typically, control information is found in packet headers and trailers. †

Padding : Per the CSS box model, the padding area of a box, that is, of an element of a document. The padding area lies between the content and border areas of a box.

Page : → Web page

Page impression : → Page view

Page parking : The quick opening of several web pages to revisit the respective pages and files at a later time. According to UX research firm Nielsen Norman Group, page parking is particularly popular among young adult users, or so-called millennials.

Page prediction : A browser feature or script which, when enabled, tells the browser to download resources the user is likely to visit before any user requests for the content are made. Page prediction improves performance by enabling almost instant loading of predicted content. However, page prediction may also download content a user does not request. ‡

Page Quality : Custom and proprietary quality criteria for web pages (Google) and Facebook Pages (Facebook).

Page view : A request to load a single HTML file (web page) of an Internet site. On the World Wide Web, a page request would result from a web surfer clicking on a link on another page pointing to the page in question. †

PageRank : An algorithm used by Google Search to rank web pages in their search engine results. PageRank was named after Larry Page, one of the founders of Google. PageRank is a way of measuring the importance of website pages. According to Google: “PageRank works by counting the number and quality of links to a page to determine a rough estimate of how important the website is. The underlying assumption is that more important websites are likely to receive more links from other websites.” Currently, PageRank is not the only algorithm used by Google to order search results, but it is the first algorithm that was used by the company, and the best known. †

PageSpeed : A family of tools by Google, designed to help a website’s performance optimization. PageSpeed was introduced in 2010. There are four main components of PageSpeed family tools: PageSpeed Module, also known as mod_pagespeed, PageSpeed Insights, PageSpeed Service, and the PageSpeed Chrome DevTools extension. All of these components are built to identify faults in a website’s compliance with Google’s web performance best practices, as well as to automate the optimization process. † ℹ︎ developers.google.com/speed

Paint : The web page rendering phase during which the final render tree is used to render the respective pixels to the screen.

Pair programming : An agile software development technique in which two programmers work together at one workstation. One, the driver, writes code while the other, the navigator or observer, reviews each line of code as it is typed in. The two programmers switch roles frequently. While reviewing, the navigator also considers the “strategic” direction of the work, coming up with ideas for improvements and likely future problems to address. This is intended to free the driver to focus all of their attention on the “tactical” aspects of completing the current task, using the navigator as a safety net and guide. †

Palpable content : Content that makes an element non-empty by providing either some descendant non-empty text, or else something users can hear (audio elements) or view (video, img, or canvas elements), or otherwise interact with (for example, interactive form controls). That elements whose content model allows flow content or phrasing content should have at least one node in its contents that is palpable (and that does not have the hidden attribute specified) is not a hard requirement. §

Paper prototyping : A method of the user-centered design process for designing and testing user interfaces. Paper prototyping is throwaway prototyping that involves creating rough, even hand-sketched, drawings of an interface to use as prototypes, or models, of a design. While paper prototyping seems simple, this usability testing method can provide useful feedback to aid the design of easier to use products. †

Paradigm : A distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitutes legitimate contributions to a field. According to Thomas Kuhn (1962), scientific paradigms are “universally recognized scientific achievements that, for a time, provide model problems and solutions for a community of practitioners.” †

Parallax scrolling : A technique in computer graphics where background images move past the camera more slowly than foreground images, creating an illusion of depth in a 2D scene and adding to the sense of immersion in the virtual experience. The technique grew out of the multiplane camera technique used in traditional animation since the 1930s. †

Parallel browsing : The keeping open and handling of several web pages in different tabs and windows.

Parameter : A special kind of variable used in a subroutine to refer to one of the pieces of data provided as input to the subroutine. These pieces of data are the values of the arguments (often called actual arguments or actual parameters) with which the subroutine is going to be called or invoked. †

Paraphrase testing : A method to test the effectiveness of content in which test participants paraphrase and explain sections that they were asked to read. Notes on the responses can be analyzed and used for follow-up questions.

Parcel : A web application bundler. Parcel was released in 2017. ℹ︎ parceljs.org

Pareto Principle : The observation that for many events, roughly 80% of the effects come from 20% of the causes. It is named after Italian economist Vilfredo Pareto, who noted the 80/20 connection in 1896, as published in his first work, Cours d’économie politique. In it, Pareto showed that approximately 80% of the land in Italy was owned by 20% of the population. It is a similar axiom of business management that “80% of sales come from 20% of clients.” †

Parkinson’s Law : The idea that work expands so as to fill the time available for its completion. Parkinson’s Law is sometimes applied to the growth of bureaucracy in an organization. It was stated in 1955 by Cyril Northcote Parkinson in an essay published in The Economist. A popular corollary is that “Work contracts to fit in the time we give it.” †

Parsed Character Data : A data definition that originated in Standard Generalized Markup Language (SGML), and that is also used in Extensible Markup Language (XML) document type definitions to designate mixed content XML elements. †

Parser : A software component that takes input data (frequently text) and builds a data structure—often some kind of parse tree, abstract syntax tree, or other hierarchical structure, giving a structural representation of the input while checking for correct syntax. The parsing may be preceded or followed by other steps, or these may be combined into a single step. The parser is often preceded by a separate lexical analyzer, which creates tokens from the sequence of input characters; alternatively, these can be combined in scannerless parsing. Parsers may be programmed by hand or may be automatically or semi-automatically generated by a parser generator. Parsing is complementary to templating, which produces formatted output. †

Parsing : The process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term “parsing” comes from Latin pars (orationis), meaning “part (of speech).” The term has slightly different meanings in different branches of linguistics and computer science. Within computational linguistics “parsing” is used to refer to the formal analysis by a computer of a sentence or other string of words into its constituents, resulting in a parse tree showing their syntactic relation to each other, which may also contain semantic and other information. †

Pascal case : Camel case with an initial uppercase letter (“TheQuickBrownFox”).

Patch : A set of changes to a computer program or its supporting data designed to update, fix, or improve it. This includes fixing security vulnerabilities and other bugs, like around functionality, performance, or usability. Patches are also called bugfixes (or bug fixes). † : → Change list

Path : The general form of the name of a file or directory, specifying a unique location in a file system. A path points to a file system location by following the directory tree hierarchy expressed in a string of characters in which path components, separated by a delimiting character, represent each directory. The delimiting character is most commonly a slash (“/”), backslash character (“\”), or colon (“:”), though some operating systems may use a different delimiter. †

PATH : An environment variable on Unix-like operating systems, OS/2, DOS, and Microsoft Windows, specifying a set of directories where executable programs are located. In general, each executing process or user session has its own PATH setting. †

Pattern : A design element or component, and a re-usable form of a solution to a design problem. †

Pattern library : A structured collection of design particles, elements, and components. May be part of a design system.

Pave the cowpaths : The idea to build on and formalize existing practices. “Pave the cowpaths” was one of the principles applied to extend the HTML standard.

Pay-per-click : An Internet advertising model used to drive traffic to websites, in which an advertiser pays a publisher (typically a search engine, website owner, or a network of websites) when the ad is clicked. Pay-per-click is commonly associated with first-tier search engines (such as Google Ads and Bing Ads). With search engines, advertisers usually bid on keyword phrases relevant to their target market. In contrast, content sites commonly charge a fixed price per click rather than use a bidding system. PPC display advertisements, also known as banner ads, are shown on websites with related content that have agreed to show ads and are typically not pay-per-click advertising. Social networks such as Facebook, Twitter, LinkedIn, and Pinterest have also adopted pay-per-click as one of their advertising models. †

Payload : The part of transmitted data that is the actual intended message. Headers and metadata are sent only to enable payload delivery. The term is borrowed from transportation, where payload refers to the part of the load that pays for transportation. †

Paywall : A method of restricting access to content via a purchase or paid subscription. Beginning in the mid-2010s, newspapers started implementing paywalls on their websites as a way to increase revenue after years of decline in paid print readership and advertising revenue, partly due to the use of ad blockers. Paywalls have also been used as a way of increasing the number of print subscribers. †

PBI : → Product Backlog Item

PCDATA : → Parsed Character Data

PDF : → Portable Document Format

Peer review : → Code review

Pen test : → Penetration testing

Penetration testing : An authorized simulated cyber attack on a computer system, performed to evaluate the security of the system. A penetration test is performed to identify both weaknesses (also referred to as vulnerabilities), including the potential for unauthorized parties to gain access to the system’s features and data, as well as strengths, enabling a full risk assessment to be completed. The process typically identifies the target systems and a particular goal, then reviews available information and undertakes various means to attain that goal. †

Perceivable, Operable, Understandable, and Robust : The four major principles of WCAG 2.0. Information and user interface components must be presentable to users in ways they can perceive; user interface components and navigation must be operable; information and the operation of user interface must be understandable; and content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. †

Perceived performance : The perception of how quickly a software feature appears to perform a task. The amount of time an application takes to start up, or a file to download, is not made faster by showing a startup screen or a file progress dialog box, however, such a feature can make the interface appear faster to the user as well as providing a visual cue to let them know the system is handling their request. †

Percent encoding : → URL encoding

Performance : The speed in which web pages are downloaded and displayed on the user’s web browser. Faster website download speeds have been shown to increase visitor retention and loyalty and user satisfaction, especially for users with slow Internet connections and on mobile devices. Web performance also leads to less data traveling across the Web, which in turn lowers a website’s power consumption and environmental impact. Some aspects which can affect the speed of page load include browser or server caching as well as image optimization. The performance of a web page can be improved through techniques such as multi-layered cache, lightweight design of presentation-layer components, and asynchronous communication with server-side components. †

Performance budget : A metrics-based set of performance-related limits for a site or app. The limits are to be controlled and not to be crossed (budget). Limits can include bundle sizes, document sizes, image weights, specific time thresholds, and also performance indices like Speed Index.

Performance indicator : → Key Performance Indicator

Perl : A family of two high-level, general-purpose, interpreted, dynamic programming languages. “Perl” refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned “sister language,” Perl 6, before the latter’s name was officially changed to Raku in 2019. Though “Perl” is not officially an acronym, there are various backronyms in use, including “Practical Extraction and Reporting Language.” Perl was originally developed in 1987 by Larry Wall as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. † ℹ︎ perl.org

Permalink : A URL that is intended to remain unchanged for many years into the future, yielding a hyperlink that is less susceptible to link rot. Permalinks are often rendered simply, that is, as friendly URLs, so as to be easy for people to type and remember. Most modern blogging and content syndication software systems support such links. Sometimes URL shortening is used to create them. A permalink is a type of persistent identifier. More often, though, persistent identifiers are called permalinks that are generated by a content management system for pages served by that system. This usage is especially common in the blogosphere. Such links are not maintained by an outside authority, and their persistence is dependent on the durability of the content management system itself. †

Persona : A fictional character created to represent a user type that might use a site, brand, or product in a similar way. Marketers may use personas together with market segmentation, where the qualitative personas are constructed to be representative of specific segments. The term “persona” is used widely in online and technology applications as well as in advertising, where other terms such as “pen portraits” may also be used. Personas are useful in considering the goals, desires, and limitations of brand buyers and users in order to help to guide decisions about a product, service, or interaction space such as features, interactions, and visual design of a website. Personas may also be used as part of a user-centered design process for designing software. †

Personal data : Any information relating to an identifiable person. The concept of personal data has become prevalent as information technology and the Internet have made it easier to collect personally identifiable information (PII) leading to a profitable market in collecting and reselling personal data. PII can also be exploited by criminals to stalk or steal the identity of a person, or to aid in the planning of criminal acts. As a response to these threats, many website privacy policies specifically address the gathering of personal data, and lawmakers such as the European Parliament have enacted a series of legislation such as the General Data Protection Regulation (GDPR) to limit the distribution and accessibility of personal data. †

Personal Home Page : → PHP

Personally identifiable information : → Personal data

PFS : Perfect → forward secrecy

PhantomJS : A discontinued headless browser used for automating web page interaction. PhantomJS provides a JavaScript API enabling automated navigation, screenshots, user behavior, and assertions making it a common tool used to run browser-based unit tests in a headless system like a continuous integration environment. PhantomJS is based on WebKit. It was first released in 2011. † ℹ︎ phantomjs.org

Phishing : The fraudulent attempt to obtain sensitive information such as usernames, passwords, and credit card details by disguising oneself as a trustworthy entity in an electronic communication. Typically carried out by email spoofing or instant messaging, phishing often directs users to enter personal information at a fake website which matches the look and feel of the legitimate site. Phishing is an example of social engineering techniques being used to deceive users. †

Phoenix : → Firefox

Photoshop : A raster graphics editor developed and published by Adobe for Windows and macOS. Photoshop was originally created in 1987 by Thomas and John Knoll. Since then, the software has become the industry standard not only in raster graphics editing, but in digital art as a whole. The software’s name has thus become a generic trademark, leading to its usage as a verb (e.g., “to photoshop”) although Adobe discourages such use. † ↑ is.gd/aAJsm0

PHP : → Hypertext Preprocessor

PhpStorm : A commercial, cross-platform IDE for PHP. PhpStorm provides an editor for PHP, HTML, CSS, and JavaScript with on-the-fly code analysis, error prevention, and automated refactorings for PHP and JavaScript code. PhpStorm was first released in 2009. † ℹ︎ jetbrains.com/phpstorm

Phrasing content : The text of an HTML document, as well as elements that mark up that text at the intra-paragraph level. Runs of phrasing content form paragraphs. §

PII : → Personally identifiable information

Pinball pattern : A pattern of user behavior in which the gaze of a user, as determined by eye tracking, “bounces around” a page, resembling how a ball moves within a pinball machine.

Ping : A computer network administration software utility used to test the reachability of a host on an Internet Protocol (IP) network. It is available for virtually all operating systems that have networking capability, including most embedded network administration software. Ping measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back to the source. †

Pinging : A colloquial expression for contacting or notifying another person.

pip : A package management system used to install and manage software packages written in Python. † ℹ︎ pypi.org/project/pip

Pixel : A physical point in a raster image, or the smallest addressable element in an all-points-addressable display device; so it is the smallest controllable element of a picture represented on the screen. Each pixel is a sample of an original image; more samples typically provide more accurate representations of the original. The intensity of each pixel is variable. In color imaging systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black. †

Pixel tag : → Tracking pixel

Pixel-perfect : The development goal of building exactly to design specs (that is, the resulting site or app looks exactly as intended, down to each pixel), as well as to have a site or app look exactly the same on all browsers and devices. In modern web development with its focus on responsive design and an indeterminable combination of browsers and devices, pixel-perfection is considered an unrealistic and problematic practice.

Placeholder : → Free variable : → Placeholder text

Placeholder text : Text that shares some characteristics of a real written text, but is random or otherwise generated. Placeholder text may be used to display a sample of fonts, generate text for testing, or to spoof an email spam filter. The process of using filler text is sometimes called greeking, although the text itself may be nonsense, or largely Latin, as with “Lorem ipsum.” †

Plain-text : A loose term for data (e.g., file contents) that represent only characters of readable material but no graphical representation or other objects and media. Plain-text may also include a limited number of characters that control simple arrangement of text, such as spaces, line breaks, or tabulation characters. It is different from formatted text, where style information is included. †

Plane : In the Unicode Standard, a continuous group of 65,536 (2^16^) code points. There are 17 planes, identified by the numbers 0 to 16, which corresponds with the possible values 00–1016 of the first two positions in six-position hexadecimal format (U+hhhhhh). Plane 0 is the Basic Multilingual Plane (BMP), which contains the most commonly used characters. The higher planes 1 through 16 are called supplementary planes. The last code point in Unicode is the last code point in plane 16, U+10FFFF. As of Unicode version 12.1, six of the planes have assigned code points (characters), and four are named. The limit of 17 planes is due to UTF-16, which can encode 2^20^ code points (16 planes) as pairs of words, plus the BMP as a single word. UTF-8 was designed with a much larger limit of 2^31^ (2,147,483,648) code points (32,768 planes), and can encode 2^21^ (2,097,152) code points (32 planes) even under the current limit of 4 bytes. The 17 planes can accommodate 1,114,112 code points. †

Platform as a Service : A category of cloud computing services that provides a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app. †

Platform modernization : → Software modernization

Playback attack : → Replay attack

Plugin : A software component that adds a specific feature to an existing computer program. When a program supports plugins, it enables customization. †

PNG : → Portable Network Graphics

Pointer : A programming language object that stores a memory address. This can be that of another value located in computer memory, or in some cases, that of memory mapped computer hardware. A pointer references a location in memory, and obtaining the value stored at that location is known as dereferencing the pointer. †

Pointing device : An input interface (specifically a human interface device) that allows a user to input spatial (i.e., continuous and multi-dimensional) data to a computer. CAD systems and graphical user interfaces (GUIs) allow the user to control and provide data to the computer using physical gestures by moving a hand-held mouse or similar device across the surface of the physical desktop and activating switches on the mouse. While the most common pointing device by far is the mouse, many more have been developed. †

Polyfill : Code that implements a feature on web browsers that do not natively support the feature. Most often, a polyfill refers to a JavaScript library that implements an HTML web standard, either an established one (supported by some browsers) on older browsers, or a proposed standard (not supported by any browsers) on existing browsers. Formally, a polyfill is a shim for a browser API. Polyfills allow web developers to use an API regardless of whether it is supported by a browser, and usually with minimal overhead. †

Polymer Project : A JavaScript library for building web applications using web components. Development of the library started in 2013, and it was released in 2015. Polymer was developed by Google. † ℹ︎ polymer-project.org

POM : → Project Object Model

POP : → Post Office Protocol

Pop-under : A variation on the pop-up window. A pop-under opens a new browser window under the active window. Pop-unders do not interrupt the user immediately, but appear when the user closes the covering window, making it more difficult to determine which website created them. Pop-unders can be considered a dark pattern. †

Pop-up : A graphical user interface (GUI) display area, usually a small window, that suddenly appears (“pops up”) in the foreground of the visual interface. Because of heavy abuse pop-ups are generally considered a dark pattern and often blocked by default. †

Port : A communication endpoint. At the software level, within an operating system, a port is a logical construct that identifies a specific process or a type of network service. Ports are identified for each protocol and address combination by 16-bit unsigned numbers, commonly known as the port number. The most common protocols that use port numbers are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). A port number is always associated with an IP address of a host and the protocol type of the communication. It completes the destination or origination network address of a message. Specific port numbers are commonly reserved to identify specific services. †

Port number : → 0–9 for various port numbers : → Port

Portable code : → Bytecode

Portable Document Format : A file format developed by Adobe in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. Based on the PostScript language, each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, vector graphics, raster images, and other information needed to display it. PDF was standardized as ISO 32000 in 2008. †

Portable Network Graphics : A raster graphic file format that supports lossless data compression. PNG was developed as an improved, non-patented replacement for Graphics Interchange Format (GIF). PNG files use the file extension png and are assigned the MIME media type image/png. PNG was published as informational RFC 2083 in 1997, and as an ISO/IEC standard in 2004. †

Portal : A specially designed website that brings together information from diverse sources, like emails, online forums, and search engines, in a uniform way. Usually each information source gets its dedicated area on the page for displaying information (a portlet); often, the user can configure which ones to display. Variants of portals include mashups and intranet “dashboards” for executives and managers. † : A mechanism that allows for the rendering and quick navigation of embedded content. ℹ︎ wicg.github.io/portals

Post mortem : A process, usually performed at the conclusion of a project, to determine and analyze elements of the project that were successful or unsuccessful. The Project Management Body of Knowledge (PMBOK) refers to the process as “lessons learned.” Project post mortems are intended to inform process improvements which mitigate future risks and to promote iterative best practices. †

Post Office Protocol : An application-layer Internet standard protocol used by email clients to retrieve email from a mail server. POP was first specified in 1984. †

PostCSS : A software development tool that uses JavaScript-based plugins to automate routine CSS operations. PostCSS was first released in 2013. † ℹ︎ postcss.org

Postel’s Law : “Be conservative in what you send, be liberal in what you accept.” Also known as the Robustness Principle, it is named after Jon Postel, who wrote in an early specification of TCP that “TCP implementations should follow a general principle of robustness: Be conservative in what you do, be liberal in what you accept from others.” †

POUR : → Perceivable, Operable, Understandable, and Robust

POW : → Packaged Offline/Online Webpage

PowerShell : A task automation and configuration management framework from Microsoft, consisting of a command-line shell and associated scripting language. Initially a Windows component only, known as Windows PowerShell, it was made open source and cross-platform in 2016 with the introduction of PowerShell Core. The former is built on the .NET Framework, the latter on .NET Core. PowerShell was first released in 2006. † ℹ︎ microsoft.com/powershell

PPC : → Pay-per-click

PQ : → Page Quality

PR : → Pull request

Pre-production environment : → Staging environment

Preact : A JavaScript library described as a lightweight alternative to React, using the same ES6 API. ℹ︎ preactjs.com

Predication : An architectural feature that provides an alternative to conditional transfer of control, implemented by machine instructions such as conditional branch, conditional call, conditional return, and branch tables. Predication works by executing instructions from both paths of the branch and only permitting those instructions from the taken path to modify architectural state. The instructions from the taken path are permitted to modify architectural state because they have been associated (predicated) with a predicate, a Boolean value used by the instruction to control whether the instruction is allowed to modify the architectural state or not. †

Prefetching : A technique for speeding up fetch operations by beginning a fetch operation whose result is expected to be needed soon. Usually this is before it is known to be needed, so there is a risk of wasting time by prefetching data that will not be used. †

Preferred style sheet : The preferred style sheet when no alternate style sheet is being selected. A style sheet can be marked as preferred by setting the link element’s rel attribute to “stylesheet” and naming the style sheet with the title attribute, as well as by using a meta element or setting a particular HTTP header.

Premature optimization : A situation where a programmer lets performance considerations affect the design of a piece of code. This can result in a design that is not as clean as it could have been or code that is incorrect, because the code is complicated by the optimization and the programmer is distracted by optimizing. †

Prerendering : The prefetching and then rendering of content in the background by a browser, as if the content had been rendered into an invisible separate tab. When the user navigates to the prerendered content, the current content is replaced by the prerendered content instantly. ‡

Presentation : In web development, the code that deals with how content is being presented. This is usually achieved through CSS (Cascading Style Sheets).

Presto : The browser engine of the Opera web browser from the release of Opera 7 in 2003 until the release of Opera 15 in 2013, at which time Opera switched to using the Blink engine that was originally created for Chromium. Presto was also used to power the Opera Mini and Opera Mobile browsers. †

Primary key : In the relational model of data, a specific choice of a minimal set of attributes (columns) that uniquely specify a tuple (row) in a relation (table). Informally, a primary key is “which attributes identify a record,” and in simple cases constitute a single attribute, that is, a unique ID. More formally, a primary key is a choice of candidate key (a minimal superkey); any other candidate key is an alternate key. †

Primitive : A data type that is either a basic type (a data type provided by a programming language as a basic building block) or a built-in type (a data type for which the programming language provides built-in support). In most programming languages, all basic data types are built-in. In addition, many languages also provide a set of composite data types. †

Principal box : A box that contains descendant boxes and generated content, and that is also the box involved in any applicable positioning scheme.

Print style sheet : A style sheet that governs print styling, using the print media type.

Privacy : The ability of an individual or group to seclude themselves, or information about themselves, and thereby express themselves selectively. The boundaries and content of what is considered private differ among cultures and individuals. When something is private to a person, it usually means that something is inherently special or sensitive to them. The domain of privacy partially overlaps with security, which can include the concepts of appropriate use, as well as protection of information. Privacy may also take the form of bodily integrity. The right not to be subjected to unsanctioned invasions of privacy by the government, corporations or individuals is part of many countries’ privacy laws, and in some cases, constitutions. †

Product Backlog : In Scrum, a prioritized list of work needed to be done to create and maintain a product. A Product Backlog is managed by the Product Owner.

Product Backlog Item : An element from a Product Backlog. PBIs can include research tasks, specifications, requirements, use cases, user stories, epics, bugs, and refactoring tasks.

Product Owner : A Scrum role that is responsible for maximizing the value of a product as well as for managing requirements and expectations for the respective product.

Production : → Production environment

Production environment : A deployment environment that is “live,” that is, that users directly interact with. When deploying a new release to production, rather than immediately deploying to all instances or users, it may be deployed to a single instance or fraction of users first, and then either deployed to all or gradually deployed in phases, in order to catch any last-minute problems. This is similar to staging, except done in production, and is referred to as a canary release, by analogy with coal mining. †

Programming : The process of designing and building an executable computer program to accomplish a specific computing result or to perform a specific task. Programming involves tasks such as: analysis, generating algorithms, profiling algorithm accuracy and resource consumption, and the implementation of algorithms in a chosen programming language (commonly referred to as coding). The source code of a program is written in one or more languages that are intelligible to programmers, rather than machine code, which is directly executed by the central processing unit. The purpose of programming is to find a sequence of instructions that will automate the performance of a task (which can be as complex as an operating system) on a computer, often for solving a given problem. †

Programming language : A formal language which comprises a set of instructions that produce various kinds of output. Programming languages are used in computer programming to implement algorithms. Most programming languages consist of instructions for computers. There are programmable machines that use a set of specific instructions, rather than general programming languages. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning). Some languages are defined by a specification document (for example, the C programming language is specified by an ISO standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. †

Progressive Enhancement : A strategy for web design that emphasizes core web page content first. This strategy then progressively adds more nuanced and technically rigorous layers of presentation and features on top of the content as the end user’s browser or Internet connection permit. The proposed benefits of this strategy are that it allows everyone to access the basic content and functionality of a web page, using any browser or Internet connection, while also providing an enhanced version of the page to those with more advanced browser software or greater bandwidth. †

Progressive font enrichment : The downloading of only the required part of a font, and the patching of the respective download with additional glyphs as needed on additional page views. The concept for progressive font enrichment has been proven, but it is not widely usable yet. ℹ︎ is.gd/g8ii9j

Progressive rendering : An approach to improve the perceived performance of a website or app.

Progressive Web App : A type of application software delivered through the Web, built using common web technologies including HTML, CSS, and JavaScript. A PWA is intended to work on any platform that uses a standards-compliant browser. Functionality includes working offline, push notifications, and device hardware access, enabling creating user experiences similar to native applications on desktop and mobile devices. While web applications have been available for mobile devices from the start, they have generally been slower, have had fewer features, and been less used than native apps. But with the ability to work offline, previously only available to native apps, PWAs running on mobile devices can perform much faster and provide more features, closing the gap with native apps, in addition to being portable across both desktop and mobile platforms. PWAs do not require separate bundling or distribution. Publication of a progressive web app is as it would be for any other web page. †

Project Object Model : A system to provide the configuration for a single project, as with a pom.xml file used for Apache Maven. †

Promise : An object that is returned by a function that has not yet completed its work. The promise literally represents a promise made by the function that it will eventually return a result through the Promise object. When the called function finishes its work asynchronously, a function on the promise object called a resolution (or fulfillment, or completion) handler is called to let the original caller know that the task is complete. ‡

Prop : An argument passed into a component. : → Property

Property : In CSS, an identifier for a CSS feature. A property has a value, and together property and value make a declaration that in turn resides in a rule. ℹ︎ w3.org/Style/CSS/all-properties : In programming, a special sort of class member, intermediate in functionality between a field (or data member) and a method. The syntax for reading and writing of properties is like for fields, but property reads and writes are (usually) translated to “getter” and “setter” method calls. The field-like syntax is easier to read and write than lots of method calls, yet the interposition of method calls “under the hood” allows for data validation, active updating (e.g., of GUI elements), or implementation of what may be called read-only fields. †

Protocol : A system of rules that allow two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics, and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. †

Prototype : In software development, a private property of an object which holds a link to another object. That prototype object has a prototype of its own, and so on until an object is reached with null as its prototype. By definition, null has no prototype, and acts as the final link in this prototype chain. ‡ : In web development and design, a more or less elaborate proof of concept or preview for a website or app.

Prototyping : The activity of creating prototypes of software applications, i.e., incomplete versions of the software program being developed. Prototyping is an activity that can occur in software development and is comparable to prototyping as known from other fields, such as mechanical engineering or manufacturing. A prototype typically simulates only a few aspects of, and may be completely different from, the final product. Prototyping has several benefits: Software designers and implementers can get valuable feedback from users early in the project, clients and contractors can compare if the software matches the specification according to which the software is built, and software engineers get insight into the accuracy of initial project estimates and whether the deadlines and milestones proposed can be successfully met. †

Proxy : → Proxy server

Proxy server : A server application or appliance that acts as an intermediary for requests from clients seeking resources from servers that provide those resources. A proxy server thus functions on behalf of the client when requesting service, potentially masking the true origin of the request to the resource server. A proxy can simplify or control the complexity of a request, or provide additional benefits such as load balancing, privacy, or security. †

PRPL : A web performance development pattern based on the sequence “Push” (important resources), “Render” (as soon as possible), “Pre-cache” (assets), and “Lazy-load.”

Pseudo-class : One of a range of predefined CSS selectors that targets elements depending on their state rather than on information from the document tree. For example, the selector a:visited applies styles only to links that the user has already followed. ‡

Pseudo-code : Code-like syntax that is used to indicate to humans how some code syntax works, or to illustrate the design of an item of code architecture. Pseudo-code does not work when tried to run as code. ‡

Pseudo-element : One of a range of predefined CSS selectors that applies styles to parts of a document content in scenarios where there is not a specific HTML element to select, but for which CSS provides an abstraction. For example, rather than putting the first letter of each paragraph in its own element, one can style them with p::first-letter. ‡

PTR : A pointer resource record in the Domain Name System (DNS). †

Pull request : → Merge request

Punycode : A representation of Unicode with the limited ASCII character subset used for Internet hostnames. Using Punycode, hostnames containing Unicode characters are transcoded to a subset of ASCII consisting of letters, digits, and hyphens, which is called the Letter-Digit-Hyphen (LDH) subset. For example, “München” (Munich) is encoded as Mnchen-3ya. †

Puppet : A software configuration management tool which includes its own declarative language to describe system configurations. Puppet is model-driven and requires limited programming knowledge to use. The tool was released in 2005, like the respective company. † ℹ︎ puppet.com

Puppeteer : A Node.js library that provides an API to control Chrome and Chromium over the Chrome DevTools Protocol. Puppeteer offers both headless and non-headless operation. ℹ︎ pptr.dev

Push notification : Small messages that can reach audiences anywhere and anytime. While pop-ups appear only when audiences are on the site they belong to, push messages are independent of sites. They are associated with web browsers and apps. †

Push technology : A style of Internet-based communication where the request for a given transaction is initiated by the publisher or central server. It is contrasted with pull/get, where the request for the transmission of information is initiated by the receiver or client. Push services are often based on information preferences expressed in advance. †

PV : → Page view

PWA : → Progressive Web App

Python : An interpreted, high-level, general-purpose programming language. Python’s design philosophy emphasizes code readability with its notable use of significant whitespace. Its language constructs and object-oriented approach aim to help programmers write clear, logical code for small and large-scale projects. Python is dynamically typed and garbage-collected. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. Python is often described as a “batteries included” language due to its comprehensive standard library. It was created in 1991 by Guido van Rossum. † ℹ︎ python.org

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