Commonly used computer terminology
This is a brief list of some commonly used terms and expressions used by computer people. It is not an exhaustive list and many of the terms can be found in greater detail in the Wikipedia.
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virtual address | An address used by a process within its virtual address space and translated by the operating system and processor to a physical memory location. |
virtual host | A web-server configuration allowing one physical or virtual server to host multiple websites or domains, commonly distinguished by the requested hostname. |
Virtual LAN | A logical network created by configuring switches so that devices can be separated into distinct broadcast domains regardless of their physical location. |
Virtual Machine | A software-based computer that runs an operating system and applications in an isolated virtual environment on a physical host computer. |
Virtual Memory | A memory-management technique that allows an operating system to use storage space as an extension of physical RAM. |
virtual package | A package-management concept representing a capability or provided interface that may be supplied by one or more actual packages. |
Virtualisation | The technique of using software to create virtual versions of computing resources such as computers, operating systems, storage or networks. |
Virus | Malware that can replicate by inserting itself into other files or programs and is typically spread when the infected host is executed. |
visudo | A Unix and Linux utility used to safely edit the sudoers configuration while checking its syntax before accepting the changes. |
VLAN | Virtual Local Area Network – a logical division of a switched network that separates devices into different broadcast domains. |
VLAN trunk | A network link configured to carry traffic belonging to multiple VLANs, normally using VLAN tagging. |
VNC | Virtual Network Computing – a technology allowing the graphical desktop of one computer to be viewed and controlled remotely. |
VoIP | Voice over Internet Protocol – technology for carrying voice communications over IP networks rather than traditional telephone networks. |
volatile | A programming-language qualifier indicating that accesses to an object may have externally observable effects and should not be freely optimised away or cached by the compiler. |
volume group | In LVM, a pool of storage composed of one or more physical volumes from which logical volumes can be allocated. |
VPN | Virtual Private Network – a technology that creates an encrypted connection over another network, commonly used to provide secure remote access or protect network traffic. |
VRAM | Video Random Access Memory – memory used by a graphics processor to store data such as images, textures and frame buffers. |
vulnerability | A weakness in software, hardware, configuration or process that could be exploited to cause unintended behaviour or compromise security. |
WAF | Web Application Firewall – a security system designed to inspect and filter HTTP traffic to protect web applications from selected classes of attack. |
WAIS | Wide Area Information Server – an early client-server information retrieval system used to search indexed collections of text and documents across the Internet. It predates the widespread adoption of Web search engines. |
wait | A Unix system call used by a parent process to wait for a child process to change state or terminate and to collect its status. |
wait-free | Describing a concurrent algorithm in which every individual operation is guaranteed to complete within a bounded number of its own steps. |
waitpid | A Unix system call used by a process to wait for a specified child process or group of child processes to change state. |
WAN | Wide Area Network – a computer network covering a large geographical area, often connecting multiple LANs. |
warm boot | Restarting a computer without completely removing electrical power, commonly using a software or hardware reset. |
Watchdog | A hardware or software mechanism that monitors a system or process and can take corrective action, such as restarting it, if it stops responding. |
watchdog timer | A hardware or software timer that takes a predefined recovery action, commonly restarting a system, if it is not periodically reset by a functioning program. |
watchpoint | A debugging facility that stops program execution when the value of a specified memory location or expression changes. |
WAV | Waveform Audio File Format – an audio file format commonly used for storing uncompressed or lightly compressed digital audio. |
Wayland | A modern display-server protocol and ecosystem intended to replace the X Window System in many Unix-like graphical environments. |
wc | Word Count – a Unix and Linux command that counts lines, words, characters or bytes in input. |
weak typing | A description applied to languages that permit relatively extensive implicit conversions between different data types. |
wear levelling | A storage-management technique that distributes writes across flash-memory cells to extend the usable life of the storage device. |
Web API | An application programming interface exposed over a network, commonly using HTTP, allowing software applications to exchange data or invoke functionality. |
Web Application | A software application delivered through a web browser and normally accessed over a network. |
Web Archive | A collection or service preserving copies of websites or web content so that pages can be accessed after their original versions have changed or disappeared. |
web cache | A cache storing web resources such as HTML, images, stylesheets or scripts so that they can be reused without retrieving them again from the origin server. |
web client | Software that communicates with web servers using HTTP or related protocols, with web browsers being the most familiar example. |
Web Crawler | An automated program that follows links and retrieves web pages for purposes such as indexing, analysis or archiving. |
Web Hosting | A service that provides storage, networking and other resources required to make websites and web applications accessible over the Internet. |
Web Ring | A collection of websites linked together in a circular navigation system, allowing visitors to move from one participating site to another. |
Web Root | The directory on a web server from which files are normally served to web clients. |
Web Server | Software or a computer system that receives HTTP requests and provides web pages, files or other resources to clients. |
Webmaster | A person responsible for maintaining, administering or developing a website. |
WebP | A modern image format developed by Google supporting both lossy and lossless compression and features such as transparency and animation. |
WebRTC | Web Real-Time Communication – a collection of web technologies and protocols allowing browsers and applications to exchange audio, video and data in real time. |
WebSocket | A communications protocol providing a persistent, two-way connection between a client and server, commonly used for real-time web applications. |
which | A Unix and Linux command that identifies the executable that would normally be selected when a particular command name is entered in the shell. |
Whitelisting | The practice of explicitly allowing a particular user, account, source, domain, or other entity to bypass a restriction or be treated as trusted. |
who | A Unix and Linux command that displays information about users currently logged into the system. |
whoami | A Unix and Linux command that displays the effective username of the current process. |
whois | A query and response service historically used to retrieve registration and administrative information associated with Internet domain names and network resources. |
Wi-Fi | A family of wireless networking technologies based on IEEE 802.11 standards, commonly used to connect devices to local networks and the Internet. |
Wi-Fi Adapter | A hardware device that provides a computer or other system with Wi-Fi wireless networking capability. |
Wildcard | A character or pattern that represents one or more unspecified characters when searching for or matching filenames, text or other data. |
Windows | A family of operating systems developed by Microsoft for personal computers, servers and other devices. |
Windows Service | A background program in Microsoft Windows that can run without an interactive user session and provide system or application functionality. |
Wine | A compatibility layer that allows many Windows applications to run on Unix-like operating systems without requiring a full Windows installation. |
word | A processor-dependent unit of data corresponding broadly to the natural size handled by a CPU instruction set. Its exact size depends on the architecture. |
Word Processor | Application software used to create, edit, format, save and print text documents. |
word size | The natural data width used by a processor architecture, commonly described in bits such as 32-bit or 64-bit. |
workaround | A method of avoiding a software or hardware problem without directly fixing its underlying cause. |
working copy | The set of project files currently checked out from a version-control system and available for modification. |
working tree | The files currently checked out in a Git repository and available for editing. |
Worm | Malware that can replicate and spread between computers or systems without requiring a user to manually copy the infected program. |
WPA2 | Wi-Fi Protected Access 2 – a Wi-Fi security standard based primarily on the IEEE 802.11i security mechanisms. |
WPA3 | Wi-Fi Protected Access 3 – a newer Wi-Fi security standard providing stronger authentication and security mechanisms than WPA2. |
write amplification | The phenomenon in which a storage device writes more physical data than the amount of data requested by the host. |
write barrier | A mechanism used to ensure that storage writes reach persistent media in an appropriate order, helping protect filesystem consistency after power loss. |
write lock | A lock providing exclusive access to a resource so that it can be modified safely. |
write-back cache | A cache in which modifications are initially stored in the cache and written to the underlying storage later. |
write-through cache | A cache in which modifications are written to the underlying storage at the same time as, or before, they are considered committed to the cache. |
X.25 | An ITU-T standard for packet-switched data communication networks, widely used before the widespread adoption of modern IP-based networking. |
X11 | The X Window System protocol and associated software traditionally used to provide graphical display and input facilities on Unix-like systems. |
X64 | A 64-bit extension of the x86 processor architecture, also commonly called x86-64 or AMD64. |
X86 | A family of processor architectures derived from the Intel 8086, including widely used 32-bit and 64-bit PC processors. |
xargs | A Unix and Linux command that constructs and executes command lines using items supplied through standard input. |
xattr | Extended Attribute – additional filesystem metadata associated with a file or directory beyond the traditional Unix permission and timestamp fields. |
XDG | Cross-Desktop Group – a set of desktop-environment specifications and conventions covering areas such as user directories, desktop application integration and configuration. |
XDG Base Directory Specification | A specification defining standard locations for user-specific configuration, data and cache files on Unix-like desktop systems. |
xfs | A high-performance journaling filesystem originally developed by Silicon Graphics and widely used on Linux systems. |
XML | Extensible Markup Language – a text-based markup language designed to represent and transport structured data. |
XMP | Extensible Metadata Platform – a metadata standard developed by Adobe for embedding and exchanging descriptive information in digital files, particularly photographs and other media. |
XMPP | Extensible Messaging and Presence Protocol – an open protocol for real-time messaging, presence information and related communications. |
XSS | Cross-Site Scripting – a web security vulnerability in which an attacker causes malicious script content to be executed in another user’s browser. |
xz | A lossless data-compression format and utility commonly used on Unix and Linux systems, providing high compression ratios using the LZMA2 algorithm. |
YAGNI | You Aren't Gonna Need It – a software-development principle discouraging implementation of functionality before there is an actual requirement for it. |
YAML | YAML Ain't Markup Language – a human-readable data serialisation format commonly used for configuration files and structured data. |
Yottabyte | A unit of digital storage equal to one septillion bytes, or 10^24 bytes using decimal SI units. |
zcat | A Unix and Linux command commonly used to display the contents of gzip-compressed files without first manually extracting them. |
zero trust | A security model based on the principle that access should not be trusted solely because a user or device is inside a particular network boundary. |
zero-based indexing | An indexing convention in which the first element of a sequence is assigned index zero. |
Zero-Day | A software vulnerability that is unknown to the vendor or for which no official security fix is yet available, or an attack exploiting such a vulnerability. |
Zettabyte | A unit of digital storage equal to one sextillion bytes, or 10^21 bytes using decimal SI units. |
ZFS | A filesystem and storage-management system designed to provide features including data integrity checking, snapshots, pooling and storage management. |
ZIP | A widely used archive file format that can store multiple files and directories, commonly with compression. |
ZMODEM | A reliable file-transfer protocol designed for efficient transfer over serial communications links, particularly popular with dial-up bulletin-board systems. |
zombie process | A terminated Unix or Linux process whose exit status has not yet been collected by its parent process. |
ZoneMinder | Free and open-source video surveillance software for Linux that can manage cameras, record video, detect events and provide remote monitoring. |
D | A compiled systems programming language designed as a successor-style alternative to C and C++. |
Dart | A programming language developed by Google and commonly used with the Flutter application framework. |
Elixir | A functional programming language running on the Erlang virtual machine and designed for concurrent and distributed applications. |
Erlang | A functional programming language designed for highly concurrent, distributed, and fault-tolerant systems. |
Fortran | A general-purpose programming language originally developed for scientific and numerical computing and still widely used in those fields. |
Go | A compiled programming language developed at Google, designed for simplicity, concurrency, networking, and systems software. |
Haskell | A statically typed, purely functional programming language known for strong type systems and lazy evaluation. |
Julia | A high-level programming language designed particularly for numerical, scientific, and technical computing. |
Kotlin | A statically typed programming language designed to run on the JVM and widely used for Android and other application development. |
Lua | A lightweight scripting language commonly embedded in applications, games, and other software. |
MATLAB | A programming language and computing environment widely used for numerical analysis, engineering, simulation, and scientific computing. |
Objective-C | An object-oriented programming language historically used extensively for software development on Apple platforms. |
Pascal | A programming language originally designed for structured programming and teaching, with descendants and implementations still in use. |
Perl | A general-purpose programming language particularly associated with text processing, system administration, scripting, and web development. |
PHP | A server-side scripting language widely used for generating dynamic web content and building web applications. |
Python | A high-level general-purpose programming language known for readable syntax and widely used in automation, web development, data science, and many other fields. |
R | A programming language and environment primarily used for statistics, data analysis, and data visualisation. |
Ruby | A high-level general-purpose programming language known for its object-oriented design and commonly used for web development and scripting. |
Rust | A compiled systems programming language designed to provide memory safety and concurrency without relying on a garbage collector. |
Scala | A programming language combining object-oriented and functional programming features and commonly used on the Java Virtual Machine. |
Swift | A general-purpose programming language developed by Apple for application and systems development. |
TypeScript | A programming language developed by Microsoft that extends JavaScript with static type checking and other language features. |
Visual Basic | A programming language and development environment associated with Microsoft's Visual Basic family of tools. |
Visual Basic .NET | A programming language targeting the .NET platform and derived from Microsoft's Visual Basic language family. |
WebAssembly | A low-level binary instruction format and execution environment designed to run compiled code efficiently on the web and other platforms. |
Compiled Language | A programming language whose source code is normally translated into machine code or another executable form before execution. |
Interpreted Language | A programming language whose programs are normally executed by an interpreter rather than being compiled directly to native machine code beforehand. |
Programming Language | A formal language used to express instructions, algorithms, and data-processing operations for computers. |
Scripting Language | A programming language commonly used to automate tasks or control other software, often with relatively lightweight execution. |