IT dictionary

Information technology (IT) leaders and their teams are expected to have technical expertise in a wide range of areas, including data management, networking, security, and enterprise transformation, among others. All areas of the business rely on IT to provide technical support and to introduce innovations the organization will need in the future.

We created this dictionary to help you learn some of the most common IT terms. You will also find links to related articles about IT teams and the technologies they build and maintain.



Responsible for supporting the configuration and operation of computer systems, servers, and network equipment, among other IT services. Also referred to as a system administrator or sysadmin.

Agile software development

An incremental and iterative approach to software development that emphasizes continual planning and delivery. Scrum, Lean, and kanban are considered agile software methodologies or systems.


Software that is used for scanning and removing viruses from a computer or network. Its purpose is to protect servers and computers and to quarantine and remove any viruses found.


A small application that performs a specific task and is run within another application. An example is a Java program that runs within a web browser.

Application protocol interface (API)

A set of commands or functions used to create software or to connect to and interact with other systems.

Application software

A program or a set of programs — such as word processors, games, spreadsheets, enterprise software, etc. — designed for use by people or end-users.

Artificial intelligence (AI)

The simulation of human intelligence processes done by machines and computer systems.


A process used to verify the identity of a person or device. Typically associated with usernames and passwords that grant access to an application, system, or website.


Big data

Extremely large datasets that are complex and cannot be processed using traditional data analysis methods.


The ledger technology at the core of bitcoin and other virtual currencies that represents chronological transactions and relationships. Blockchain makes the history of a digital asset unchangeable, decentralized, and transparent. Blockchain is also referred to as Distributed Ledger Technology (DLT).

Business continuity plan

A planning process that helps companies prevent business disruption and speeds up recovery in the event of a natural disaster, pandemic, threat, or instance of sabotage.


Stands for Bring Your Own Device and is the practice of allowing company employees to use their personal devices like laptops, smartphones, and tablets for work purposes.



Computer memory that stores recently used information to enable quicker access.


A device that accesses data stored on a central server. There can be many computers or devices ("clients") accessing data on one server that’s physically located elsewhere.

Closed source

Refers to software that is proprietary, or in other words, is owned by an organization.

Cloud computing

The practice of using remote servers hosted on the internet to store, manage, and deliver services and applications. Cloud-based can refer to different types of productivity tools, games, and other personal or business software and services that are held remotely from the end-user.

Command line interface

A text-based interface for entering commands that instruct a computer program to do specific tasks.

Configuration management

The process for configuring and maintaining consistent records for system integrity and updates — across hardware, software, and other system components.

Continuous delivery

The ability to deploy code changes (such as new features, configuration changes, and bug fixes) at any time. This approach uses small build cycles to package software for deployment in a production-like environment so it can be rapidly deployed. Read more about "continuous everything."

Continuous deployment

A process by which changes to software code are automatically deployed to the final production environment. Automatic run tests ensure the code functions properly before it is deployed. Read more about "continuous everything."

Continuous integration

A software development practice that requires engineers to continuously integrate or merge code into a shared repository. Automated build and test processes help teams quickly identify code issues. Read more about "continuous everything."


Encompasses the use of technologies, practices, and policies to stop unauthorized access and damage to data, networks, devices, and programs.


Data center

A grouping of off-site network servers that companies use to store, process, and transfer large amounts of data.

Data loss prevention (DLP)

A set of tools and processes used to monitor and block the unauthorized flow of information.

Data mining

A process that analyzes large amounts of raw data within a database to look for patterns and specific information.


Refers to the structure, organization, and storage of electronic data.


A set of software development practices that combines development (Dev) and IT operations (Ops) for the continuous delivery of reliable software. Read more about DevOps.


An extension of DevOps that integrates security (Sec) into the DevOps process.

Digital transformation

The use of digital technologies to create new customer experiences and business processes or to optimize existing ones. Read more about digital transformation.

Disaster recovery

The process of identifying how business operations will be resumed following an unexpected or disastrous event.

Domain name system (DNS)

A naming system that translates domain names into Internet Protocol (IP) addresses. This allows users to access a website on the internet by searching for its unique domain name.

Dynamic Host Configuration Protocol (DHCP)

A network protocol that automatically assigns an IP address to each device that is connected to a network.



The process that converts sensitive data into an unrecognizable form to protect it from unauthorized access.

Enterprise transformation

Describes the change that is taking place in large companies to deliver better customer experiences. Enterprise transformation involves innovations in technologies, processes, and people. Read more about enterprise transformation.


A standard means of using a wire to connect devices like computers on a network to routers and switches.

Everything as code

A concept that refers to treating systems and their components — including operating systems, network configurations, and infrastructure — as code.

Extensible Hypertext Markup Language (XHTML)

A common markup language used in the past for creating webpages. It has been since replaced by HTML5.

Extensible Markup Language (XML)

A meta-language that defines documents of a standard format so they can be read by a compatible application and can be used with HTML pages.


File Transfer Protocol (FTP)

A protocol designed for transferring files over the internet. Files stored on an FTP server can be accessed using an FTP client, which is operated through a web browser, FTP software program, or a command line interface.


Hardware or software that acts as a barrier to the internet to protect a network from untrusted, outside connections while allowing trusted connections through.


A set of instructions or programs on a device that dictates how it should communicate with other computer hardware.



Hardware such as a router or server that enables traffic to flow to and from different networks.

Graphical user interface (GUI)

An interface that carries out computer commands using icons, menus, and buttons.

Group authentication

A security protocol used to verify which users belong to a group and to grant or deny access to information based on that group.



Tools, machinery, and other durable equipment such as keyboards, monitors, or central processing units.

Hardware as a service (HaaS)

Managed services and hardware that are leased from a service provider for a monthly fee.

Help desk

Refers to a team or function within a company that provides technical support — for tools, products, or services — to internal or external customers.


A type of computer or server that is accessible over a network with a unique identifier called a hostname. Other computers, often called clients, access the host.

Hypertext Markup Language (HTML)

A website language used to create webpages. The term "hypertext" refers to the hyperlinks within a webpage and the term "markup language" refers to tags that define the webpage layout and elements.

Hypertext Transfer Protocol (HTTP)

An application protocol used to enable communication between a user's browser and a web server.

Hypertext Transfer Protocol Secure (HTTPS)

An extension of HTTP that uses encryption protocol to ensure secure communication between a user's browser and a web server.


Software used to manage one or more virtual machines (VMs). It allows each VM to access computer hardware.


Idea management

The process of capturing, sorting, and prioritizing ideas from customers, partners, and internal teams. Effective idea management is vital for understanding what customers want and driving innovation. Read more about idea management.

Infrastructure as code (IaC)

A method for configuring infrastructure that allows operations teams to manage and provision it automatically using code.

Infrastructure as a service (IaaS)

A form of cloud technology that delivers essential computing resources like networks and storage to consumers and companies on-demand on a pay-as-you-go basis.

Integration (application)

Point-to-point interactions between two software applications that synchronize data and workflows.

Integration testing

A type of software testing where individual units are combined and tested to ensure they work as intended together.

Internet Protocol (IP) address

A set of numbers assigned to a device to connect it to a computer network that uses the internet.

Internet Protocol security (IPsec)

A network protocol suite used to validate and encrypt packets of data and provide secure internet communication between computers.

IT assessment

The process of analyzing the state of a company’s IT environment, including processes, policies, infrastructure, resources, and capabilities — to identify strengths, risks, and areas for improvement.

IT Infrastructure Library (ITIL)

ITIL is a framework of best practices for achieving IT-business alignment. ITIL V3 (ITIL 2011) organizes ITIL processes around these five service lifecycle stages: Service Strategy, Service Design, Service Transition, Service Operation, and Continual Service Improvement. Read more about ITIL.

IT plan

A plan that defines how IT teams and their key initiatives will serve company-wide goals. An IT plan can cover IT strategy, IT governance, IT leadership, and more. Read more about IT plans.

IT roadmap

A visual representation of how an IT team is going to meet a set of business objectives and the technical work required to get there. Roadmaps are used to communicate technology initiatives and the progress against the plan. Read more about IT roadmaps.

IT service management (ITSM)

ITSM is a set of policies and processes for planning, delivering, and supporting IT services. Read more about ITSM.

IT strategy

Identifies how IT will be used to support the needs of the business and determines the direction of all IT activities, roles, and resources. Read more about IT strategy.



Client-side scripting language commonly used in web development.


Kanban board

Visual card-based representation of work and workflow. Cards represent work and columns represent each stage of the process. As work progresses, cards move from left to right across the board. Kanban boards can be digital or physical. Read more about kanban boards.


An agile development methodology that helps teams work more efficiently by visualizing work, limiting work-in-progress, and maximizing flow. Read more about kanban.


The core layer of a computer operating system (OS) that communicates with all hardware and manages computer resources.



Sometimes referred to as network or disk latency, this refers to a delay in transmitting or processing data.

Local area network (LAN)

Refers to a network of connected devices within a specific location, such as a home or business location.


Machine language

Consists of binary digits (ones and zeros) or other programming languages that are compiled before the code is run on a computer.

Machine learning

A type of artificial intelligence (AI) that learns and evolves over time by identifying patterns based on input.


A powerful computer developed for high-volume, processor-intensive computing used by large businesses and institutions.


Software that is designed to cause damage to a computer, steal information, or execute other destructive functions.


A method of developing applications as a collection of services that are modular, loosely coupled, and highly scalable.


Network as a service (NaaS)

A form of cloud technology that delivers networking resources such as Wide Area Networks (WANs) and Virtual Private Networks (VPNs) to companies from one centralized point. Services are offered on-demand on a pay-as-you-go basis.

Network monitoring

An IT process that monitors network technology, including routers, firewalls, and servers for defects and performance issues to ensure everything is optimized.

Network security

A set of rules and configurations that is designed to protect the integrity and accessibility of data and various types of technologies, devices, and processes on networks.

Network topology

Refers to the way various systems on a computer network are structured, connected, and arranged. Common network topologies include star, ring, line, bus, and tree configurations.


Open source

A program's code that is available for free to the public and accessible by anyone. Open source software can be created and modified by an individual, group, or company without concerns over copyright or intellectual property.

Open Systems Interconnection (OSI)

A model created by the International Organization for Standardization (ISO) that standardizes communication between computer systems and divides communications into layers including physical, data, network, transport, session, presentation, and application layers.

Operating system (OS)

Primary system software that a computer or device needs to start and run. The OS communicates with the hardware and other computer programs.



A set of changes that are developed and applied to a computer program to update it or fix an identified problem. Patches might apply to security vulnerabilities or software issues like bugs.


Unsafe or fraudulent emails that appear to come from legitimate websites but are intended to scam or mislead the recipient.

Platform as a service (PaaS)

A form of cloud technology whereby a service provider delivers an on-demand, pay-as-you-go platform to its clients. This helps the client develop, run, and manage business applications without having to purchase expensive infrastructure.

Private cloud

Consists of internal or external computing resources that can only be accessed by a single organization. Private clouds are customized to meet specific IT requirements, such as increased security.


An executable script or software that consists of compiled code that runs on a computer operating system.


A standardized set of rules that enable devices to communicate with each other through transmitted data.


The process of preparing new systems for users, generally virtualized or on-demand.


Quality of service (QoS)

Refers to any technology that manages data traffic to reduce latency and loss on the network. May prioritize important traffic to be delivered ahead of other traffic to improve network performance.


Code that is written to retrieve information from a database.


Regression testing

A type of software testing used during software development to confirm that code changes are running as intended.

Remote backup

An online data backup service run by a remote, cloud-based server.

Robotic process automation (RPA)

A program that simulates the actions of a human. RPA interprets, triggers responses, and communicates with other systems to perform a variety of repetitive tasks.



A popular agile development methodology that emphasizes iteration and adaptation. Cross-functional teams work together to achieve a shared goal within a set period of time (usually two to four weeks). Read more about scrum.


Computer hardware or software that provides data, services, and functionality to other devices or clients. Common servers include database servers, mail servers, and web servers.

Service level agreement (SLA)

A service-related agreement or contract that outlines a set of deliverables and parameters that a service provider and their client(s) have agreed upon.

Single sign-on (SSO)

A method of securely authenticating and signing on to multiple applications or websites using just one set of credentials.

Software as a service (SaaS)

A software delivery method whereby a service provider can offer customers the use of web-based software on a pay-as-you-go model over the internet.

Software development kit (SDK)

A set of software tools and programs used by developers to create applications for specific platforms.


Refers to software that spies on computers to capture sensitive and valuable information like passwords, financial information, and usernames.

Systems development life cycle (SDLC)

A structured approach for developing software that incorporates planning, designing, building, testing, and implementing software.


Technology stack

The combination of programming languages, tools, services, and software that run an application or underpin a development project.

Test-driven development (TDD)

Instead of writing code first and then testing it, as in traditional development, TDD starts with a series of tests — followed by coding (and code revisions) until the code passes the tests.

Thick client

A computer that performs the majority of its own processing in client/server applications.

Thin client

A computer that does not store data on its own hard drive but instead accesses data from a central server.

Transmission Control Protocol (TCP)

A fundamental protocol, categorized as a transport layer, that allows systems to communicate over the internet. It creates and maintains connections between hosts.

Transmission Control Protocol/Internet Protocol (TCP/IP)

Refers to two protocols developed by the U.S. military to allow computers to communicate over long-distance networks. TCP verifies delivery of the packets while IP moves data packets between nodes. TCP/IP is now foundational to the internet.


Unit testing

A software testing method meant to identify bugs early in the development process. Applications are separated into small parts, or units, that are tested individually and independently. Unit testing is an important element of test-driven development. Read more about unit testing.


A common metric used to describe system reliability. Uptime is defined in terms of days available out of 365 (e.g. 355) or as a percentage out of 100 (e.g. 95.5%).


Describes whether a user interface (UI) is easy to use. Usability is a key feature of user experience (UX).

User acceptance testing

Software tests done in the final phase of testing where the end user tests and verifies that the software meets requirements before it is deployed to production.

User Datagram Protocol (UDP)

A communications protocol that is used to speed up data transmissions for time-sensitive communications like domain name system (DNS) or video and audio playback. UDP is an alternative to Transmission Control Protocol (TCP).

User experience (UX)

Describes the total experience that a user has when accessing and using hardware, software, or a service. Typically refers to how intuitive or enjoyable the experience is. Read more about user experience.

User interface (UI)

Describes how a user controls a particular software program. Users tend to judge a UI by how easy it is to use (usability) and how quickly they can accomplish a given task.


Virtual private network (VPN)

A secure, encrypted connection over the internet from a device to a network. VPNs are used for enhancing security and privacy.


The process of creating a virtual or software-based representation of a resource — such as a virtual server, application, operating system, storage, or network. Virtualization allows for efficient distribution of resources and cost-savings for IT.


Malicious programs or scripts designed to negatively impact computers or servers by creating files, relocating, and/or deleting files so that computers no longer function properly.

Voice over Internet Protocol (VoIP)

Technology that delivers voice communications and multimedia over Internet Protocol (IP) networks so you can make calls over the internet rather than using a traditional phone line.


Wide area network (WAN)

A number of smaller local area networks (LANs) that are interconnected. WANs are significantly larger and typically span longer distances via telephone lines, fiber optic cables, or satellite links.

Wireless local area network (WLAN)

Refers to a local area network (LAN) that allows devices to communicate without the use of any cables.


Extensible Hypertext Markup Language (XHTML)

A common markup language used in the past for creating webpages. It has been since replaced by HTML5.

Extensible Markup Language (XML)

A metalanguage that defines documents of a standard format so they can be read by a compatible application and can be used with HTML pages.


YAML Ain’t Markup Language (YAML)

A human-readable data-serialization language commonly used for configuration files and applications where data is stored or transmitted. It targets the same communications applications as XML but uses minimal syntax.


Zero-day exploit

Refers to a malicious software vulnerability that is not yet known to the people who will need to address any resulting vulnerabilities, giving them zero days to prepare.


A commonly used type of software that creates a compressed version of a file to reduce the space it takes up during storage and transmission.

Zone file

Provides information about one or more domain names, including a list of DNS records. Zone files define the IP address of a domain name and contain DNS and mail server information.

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