Glossary of Computer A to Z

Glossary of Computer A to Z– A glossary also known as vocabulary of terms, Basically it is an alphabetical list of word, it helps us find any word from the dictionary of technology.


Access Control :– It is a way of limiting access to a system or to physical or virtual resources.

Access Time :- The time interval between the instance at which data is called from a storage device and the instance when delivery begins.

Accumulator :- A local storage area called a register, in which the result of an arithmetic and logic operation is formed.

Active Cell :- It refers to the currently selected cell in a spreadsheet. It can be identified by a bold outline that surrounds the cells.

Active Window :- It is the currently focused window in the current window manager.

Algorithm :- In computing, an algorithm is a procedure for accomplishing some tasks which given an initial state, will terminate in a detinned end-state.

Alphanumeric:- A character set that contains letters, digits and other special character such as @,$,+,*,%,etc.

Antivirus:- It consists of computer programs that attempt to identify threat and eliminate computer viruses and other malicious software (malware).

Application Software:- It is a subclass of computer software that employs the capabilities of a computer directly to a task that the user wishes to perform.

Achieve:- It provides backup storage.

Arithmetic Logic Unit (ALU):- It is a part of the execution unit, a core component of all CPUs. ALUs are capable of calculating the results of a wide variety of basic arithmetical and logical Computations.

Artificial Intelligence:- Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications,
such as voice recognition, that are being used today.

 ASCII(American Standard Code for Information Interchange):- It is a character set and a character encoding based on the Roman alphabet as used in Modern English and other Western European languages.

Assembler:- A program that translates mnemonic statement into executable instruction.

Attribute:- The characteristics of an entity are called its attributes.

Authentication:- It is a process in which the credentials provides are compared to those on file in a database.

Auxiliary Memory:- It is also known as secondary memory that is not directly addressable by the CPU.


Backspace Key:- This key is used to delete the text backspace will delete the text left side of the cursor.

Backup:- A copy of a file or other item of data made in case the original is lost and damaged.

Bandwidth:- The maximum amount of data that can travel in a communication path in a given time, measured in bits per second (bps).

Bar Code:- It is a machine-readable representation of information in a visual format on a surface.

Batch File:- It is a text file that contains a sequence of commands tor a computer operating system (LDOS).

Binary Coded Decimal:- (BCD) A coding system in which a 4 digit binary number represents each decimal digit from 0 to 9.

Bit:- It is the most basic information unit used in computing and information theory.

Blog:- It is a discussion or informational site published on the world wide web.

Bomb:- A type of virus designed to activate at a specitic date and time on your computer.

Bluetooth:- A protocol that permits a wireless exchange of information between computers, cell phones and other electronic devices.

Booting:- It is a bootstrapping process which starts the operating system when a computer is switched ON.

Browser:- A special software that enables users to read/view Web pages and jump from one Web page to another.

Buffering:- The process of storing data in a memory device, allowing the devices to change the data rates, perform error checking and error retransmission.

Bug:- A software bug is an error, flaw, failure, or fault in a computer program or system that produces an incorrect or unexpected result.

Bus:- A circuit that provides a communication path between two or more devices of a digital computer system.

Byte:- It is commonly used as a unit of storage measurement in computers, regardless of the type of data being stored.


Cell:- A box in a spreadsheet, in which you can enter a single piece of data.

Central Processing Unit (CPU):- It performs the actual processing of data. The CPU is generally called by its generic name Processor. It is also known as the brain of computer.

Channel:- A communication channel can be a physical link, such as a cable that connects two stations in a network or it can consist of some electromagnetic

Chatting:- Typing text into a message box on a screen to engage in dialog with one or more people via the Internet or other network.

Chip:- A tiny wafer of silicon containing miniature electric circuits that can store millions of bits of information.

Client-Server:- It is a network architecture which separates the client from the server. Each instance of the client software can send requests to a server or application server.

Coding:- It means the transformation of data into a form understandable by computer software.

Command:- It is a directive to a computer program acting as an interpreter of some kind, in order to perform a specific task.

Compile:- It is the process of converting high level languages to machine language.

Compiler:- It is a computer program that translates a series of instructions from high level language to machine language.

Communication Protocol:- It is a system of rules that allow two or more entities of a communications system to transmit information.

Computer Network:- It is a system for communication among two or more computers.

Computer Graphics:- These are visual presentations on a computer screen. Examples are photographs, drawings, line arts, graphs or other images.

Cold Boot:- When a computer restarts after the power cut, is called cold boot.

Control Panel:- It is the part of Windows menu, accessible from the Start menu, which allows users to view and manipulate basic system settings and controls, such as adding hardware, adding/removing8 software, controlling user accounts, changing accessibility options, etc.

Computer Worm:- It is a self-replicating computer program, similar to a computer virus.

Control Unit:- It is the part of a CPU that directs its operation. The outputs of this unit control the activity of the rest of the device.

Corel Draw:- A vector graphic edit software which is known as corel draw. It is mainly used in DTP (Desktop Publishing).

Crawler:- It is an Internet bot that systematically browse the world wide web, typically for the purpose of Web indexing. It is also called a Web spider.

Cryptography:- The conversion of data into a secret code for transmission over a public network.

Cut:- To remove an object from a document.


Data:- It is a collection of facts and figures which are not in directly usable form.

Database:- It is a collection of logically related information in an organised way so that it can be easily accessed, managed and updated.

Data Abstraction:- It is a simplified view of an object that includes only features one is interested in while hides away the unnecessary details.

Data Entry:- Direct input of data in the appropriate data fields of a database known as data entry.

Database Management System:- It is a collection of various programs. It provides a systematic way to Create, retrieve, update and manage data.

Data Processing:= Converting data into information, is called data processing.

Data Redundancy:- It is a condition created within a database or data storage technology in which the same piece of data is held in two separate places.

Data Flow Diagram (DFD:- It is a graphical representation of the flow of data through
information system. Debugging A methodical process of finding and reducing the number of bugs, or defects are known as debugging.

Degree:- The number of fields associated with the database table or relation.

Desktop Publishing (DTP):- It combines a personal computer, page layout software and a printer to create publications on small economic scale.

Device Driver:- A device driver, often called a driver for short, is a computer program that enables another program, typically, an operating system to interact
with a hardware device.

Dial-up Line:= A line through which communication established known as dial-up line.

Digital Clock:- A type of clock that located on motherboard and display digital signals.

Direct Access:- It is the capability of the computer equipment to obtain data from a storage device.

Directory:- In computing, a directory is an entity in a file system which contains a group of files and other directories. Together, the directories form a hierarchy
or a tree structure.

Domain Name:- A unique name that identifies a particular Website and represents the name of the server where the Web pages reside.

Dots Per Inch (DPI):- It is defined as the measure of the resolution of a printer, scanner or monitor. It refers to the number of dots in a one inch line.

Download:- It refers to the act of transmitting data from a remote computer on the Internet or other network to one’s own computer.

Drag and Drop:- In computer graphical user interfaces, drag and drop is the action of clicking on a virtual object and dragging it to a different location or onto another virtual object.

Dumb Terminal:- A computer terminal with no processing or programming capabilities, generally used for simple data entry or retrieval tasks.

DVD:- It is an optical disc storage media format that can be used for data storage including movies with high quality video and sound.

Dynamic RAM DRAM:- is a type of random access memory which stores each bit of data in a separate capacitor.


EBCDIC (Extended Binary Coded Decimal Interchange Code):- It is an 8-bit character encoding used on 1BM mainframe operating systems, like Z/OS, S/390, AS/400 and i5/OS.

E-Commerce:- Electronic commerce is a type of industry where buying and selling of product or services is conducted over electronic systems such as the Intranet and other computer network. Editing The process of changing information by inserting, deleting, replacing, rearranging and reformation.

Electronic Data Processing (EDP):- A data processing through equipment that is predominantly electronic such as digital computer.

Electronic mail:- E-mail is a method of composing, sending, storing and receiving messages over electronic communication systems.

Encryption:- In cryptography, encryption is the process of encoding messages (or information) in such a way that hackers cannot read it, but the authorised users
can access it.

End User:- Any individual who uses the information generated by a computer based system.

Entity:- It is something that has certain attributes or properties which may be assigned values.

Error Message:- It is information displayed when an unexpected condition occurs usually on a computer or other device.

Escape Key:- A key that permits the user to leave one segment of a program and move to another.

Excel:- It allows users to create spreadsheets much like paper ledgers that can perform automatics calculations.

Exe (exe):- It is a common filename extension denoting an executable file (a program) in the DOS; MS Windows.

Execution Time:- The total time required to execute a program on a particular system.

Expansion Slot:- It is ‘a socket on the motherboard that is used to insert an expansion card which provides additional features to a computer.

Extranet:- A technology that permits the users of one organization’s Intranet to enter portions of another organization’s Intranet in order to conduct business transactions or collaborate on joint projects.


Fax It stands for ‘Facsimile’. It is used to transmit a copy of a document electronically.

Field The attributes of an entity are written as fields in the table representation.

File:- A collection of information stored electronically and treated as a unit by a computer. Every file must have its own distinctive name.

File Allocation Table (FAT):- It is the name of a computer file system architecture. The FAT filesystem is a legacy file system which is simple and robust.

File Manager:- It is an operating system utility that provides a user interface to work with file systems.

Firewall:- A security system usually consisting of hardware and software that prevents unauthorised persons from accessing certain parts of a program
database or network.

Flowcharts:- These are the means of visually representing the flow of data through an information processing system, the operations performed within the system and the sequence in which they are performed.

Foreign Key:- A field in a database table, which links it to another related table.

Format :-To set margins, tabs, font or line spacing in layout of a document.

Its name stands for formula translating system. The language was designed at IBM for scientific computing.

Freeware:- A form of software distribution where the author retains copyright of the software but makes the program available to others at no cost.

Function Key:-
A special key on a computer keyboard or a terminal devices keyboard that is used to perform specific functions, Many keyboards have function keys labelled from F1 to F12.


Garbage In Garbage Out:- (GIGO) It pertains to the fact that most computer errors are not machine errors, they are data errors caused by incorrect input data.

Gateway:- A device that is used to joint together two networks having different base protocols.

Gigabyte (GB):- It is a unit of information or computer storage equal to approximately one billion bytes.

Gigahertz (GHz):- A measurement used to identify the speed of the central processing unit. One gigahertz is equal to 1 billion cycles per second.

Graphic Display Unit (GDU):- It is also known as Visual Display Unit. This displays characters graphics representing data in a computer memory.

Graphic Interchange Format (GIF):- A simple file format for pictures and photographs, that are compressed so they can be sent quickly.

Graphic Tablet:- It is an input device which is used to create images, etc.

Graphical User Interface (GUI):- It is a method of interacting with a computer through a metaphor of direct manipulating of graphical images and widgets
in addition to text.


Hacker:- A computer criminal who penetrates and tempers with computer programs or systems.

Hang:- To crash in such a way that the computer does not respond to input from the keyboard or mouse.

Hard Copy:- It is a printed copy of information from a computer.

Hard Disk:- It is a non-volatile data storage device that stores data on a magnetic surface layered onto disk platters.

Hardware:- The mechanical, magnetic, electronic and electrical components that comprises a computer system such as CPU, monitor, keyboard, mouse, etc.

High-Level Programming Languages:- It is a programming language that is more user-friendly, to Some extent platform-independent and abstract from low-level computer processor operations such as memory accesses.

Home Page:- A starting point or a doorway to the Website,. It refers to the Web page that identities a Website and contains the hyperlink to other Web pages in the Website.

Host Computer:-
A computer that provides information or a service to other computers on the Internet. Ever host computer has its own unique host name.

Hub:- A network device that connects multiple computers on a LAN, s0 that they can communicate with one another.

Hybrid Computer :-Hybrid computers are made by taking the best features of the analog computer and digital computer. A simple example of this type is the
computer used in hospitals.

Hyperlink:- An image or portion of text on a Web page that is linked to another Web page.

Hyper Text Markup Language:- It stands for HTML. It is mainly used for design Websites.

Hyper Text Transfer Protocol (HTTP):- It is an important protocol used on the world wide web for moving hypertext files across the Internet,


Icon:- A symbol (such as picture or a folder) that Icon represents a certain function on your computer. When the user clicks on the icon, the appropriate function is executed.

Information:- It is the summarisation of data according to a certain pre-defined purpose.

Input:- In order to give instructions to a computer, the information has to be supplied to it.

Instant Messaging (IM):- A chat program that lets people communicate over the Internet in real time.

Instruction:- A command or order given to a computer to perform a task.

Instruction Cycle:- Fetching and decoding operations of the machine cycle.

Interface:- A device or program that helps a user to communicate with a computer.

Interpreter:- A program that converts and executes the source code into machine code line by line.

Internet:- A vast computer network linking smaller computer networks worldwide.

Internet Surfing:- To search something on Internet is called Internet surfing.

Internet Service Provider (ISP):- It is a business organisation that offers users access to the Internet and related services.

Integrated Circuits:- Multiple electronic components combined on a silicon chip.


Java:- A programming language, used to crate mobile applications, software etc.

Javascript:- It is an object oriented programming language used to create interactive effects in a Web browser.

JPEG (join photographic expert group):- it is a commonly used method of compression for digital photography.

Joystick:- it is a computer peripheral expert general control device consisting of a handheld stick that pivots about one end and transmit its angle in two or three dimensions to a computer.


Kernel:- it is the fundamental part of program, such as an operating system, that resides in memory at all times.

Keyboard:- this is the standard input device attached to all computer. the layout of keyboard is just like traditional typewriter of the type QWERTY.

Key Field:- A unique field in a record used to distinguish one record from another.

Key Stroke:- It is the process of pressing button in keyboard.

Kilobyte (KB):- It is a unit of information or computer storage equal to 1024 bytes.


LAN:- LAN stands for Local Area Network. In a LAN. the connected computers are geographically close together. They are either in the same building or within that lets smaller area.

Laptop:- It is a small, lightweight and portable battery-powered computers that can fit onto your lap. They each have a thin, flat and liquid crystal display screen.

Light Pen:- A light sensitive style for forming graphics by touching coordinates on a display screen, thereby a user to seeming to draw directly on the screen.

Link:- A communication path between two nodes or channels.

LINUX:- It is an open source operating system, meaning smaller that the source code of the operating system is freely available to the public.

List Processing (LISP):- A high level programming language suitable for handling logical operations and non-numeric applications.

Log In:- It is the process by which an individual gains access to a computer system by identifying and authenticating themselves.

Log Off:- It is a process of withdrawal from function after performing program.

Low Level Language:- It is a assembly language which is used in computer, it was mostly used in first generation computers.


Machine Language:- The language of computer also called binary language. Instructions in this language are written as a sequence of of 0’s and 1’s.

Mainframe:- Sometimes it’s called a server or CPU. Mostly a mainframe is only a mainframe when compared to a desktop computer. It is bigger and much more powerful.

Mass Storage:- It is referred to storage where large such volumes of backup/data is stored.

Megabyte (MB):- 1 Megabyte is equal to 1048576 bytes, usually rounded off to one million bytes. It is also called a “meg”.

Memory:- Temporary storage for information, including applications and documents.

Menu Bar:- The horizontal strip across the top of an application’s window. Each word on the strip has a context sensitive drop-dowm menu containing features and actions that are available tor the application in use.

Merge:- Combining two or more files into a single file.

Microcomputer:- A microprocessor based computer, junction consisting of an CPU, internal semiconductor memory, input and output sections and a system bus, all on one, Non-Volatile or several monolithic 1C chips inserted into one or data several PC boards.

Microprocessor:- A complete Central Processing Unit Notebook (CPU) contained on a single silicon chip.

Midi:- It stands for Music Instrument Digital Interface. It Object allows a computer to store and replay a musical instrument’s output.

Minicomputer:- Considered to be more capable than a Object microcomputer but less powerful than a mainframe.

MIPS:- An acronym derived from Million of Instructions Offline Per Second. It is used to measure the speed of a processor.

Mnemonic:- A symbolic label or code remainder that Online assists, the user in remembering a specific operation or command in assembly language.

Modem:- An acronym for Modulator/Demodulator that refers to specific equipment that provides a means of communication between two computer systems over
Operation conventional telephone lines.

Monitor:- The visual readout device of a computer system. A monitor can be in several forms; a Cathode Ray Tube Operating (CRT), a Liquid Crystal Display (LCD), or a flat-panel, full-color display.

MS-DOS (Microsoft Disc-Operating System):- An early operating system developed by Microsoft Corporation.

Multitasking:- It can simultaneously work with several Output programs or interrelated tasks that share memories, Patch codes, buffers and files.

Multithreading:- It is a facility available in an operating Peripheral system that allows multiple functions from the same application packages.

Multimedia:- Software programs that combine text and Personal graphics with sound, video and animation. A multimedia PC contains the hardware to support these capabilities.


Network:- It is an interconnection of two or more than two computer.

Network Interface Card (NIC):- This is a part of the computer that allows it to talk to other computers via a network protocol like TCP/IP.

Nibble:- A sequence of four adjacent bits, or a half byte. A hexadecimal or BCD coded digit can be represented by a nibble.

Node:- The endpoint of a network branch or the junction of two or more branches.

Non-Volatile Memory:- A memory where stored one, data remains undisturbed by the removal of electrical power.

Notebook:- A portable computer, that can fit into a briefcase. It is used as personal computer. It is also called laptop.


Object:- Something that contains both the data and the application that operate on that data.

Object Code:- Machine language code produced by a translator program, such as an assembler, interpreter, or compiler.

Offline:- It refers to the state in which a computer is temporarily or permanently unable to communicate with another computer.

Online:- It refers to the state of being connected to the networked computer system or the Internet.

Operand:- The part of a machine level instruction which tells the central processor, the location of the data to be manipulated by some operation.

Operation Code (Op-Code):- Part of a computer instruction word that designates the function performed by a specific instruction.

Operating System:- A set of instructions that tells a computer on how to operate when it is turned ON. It sets up a filing system to store files and tells the computer how to display information on a video display.

Output:- Data that come out of a computer device.


Patch:- A small program that improves an existing piece of software or corrects an error in it.

Peripheral:- An auxiliary device used to put information into and get information out of the computer.

Personal Computer:- (PC):- A single-user computer containing a Central Processing Unit (CPU) and one or more memory circuits.

Piracy:- The illegal copying of software or other creative works.

Pixels:- An acronym derived from picture element. The smallest element (a dot) on a display screen.

Plug-In:- This is a program that your browser uses manipulate a downloaded file.

Portrait A term that designates the position of conventional printing across the width of a page.

Past Office Protocol (POP):- A protocol that specifies how a personal computer can connect to a mail the server on the internet and download E-mail

Primary Key:- It is a key that uniquely identifies each tuple or row in a table.

process:- A collection of code, data and other system resources including at least one thread of execution that performs a data processing task.

Program:- A set of instructions to perform a specific task

Programming Language:- A vocabulary and set of grammatical rules tor instructing a computer to perform specific tasks.

Prompt:- An onscreen symbol, (e.g. cursor) that indicates where to type of command.

Printer:- A mechanical device for printing a computer’s output on paper.

Protocol:- A set of rules that defines exactly how information is to be changed between two systems over Internet.

Pseudocode:- It is a short hand way of describing a computer program


Query:- A request for information from a database.


Random Access Memory (RAM):- A volatile, Software semiconductor storage structure that accesses temporary data with a random or direct accessing
method. Data in this memory can be read by the Source CPU directly.

Read Only Memory (ROM):- A semiconductor memory whose data cannot be erased, or overwritten; it can only be accessed (read) for use by the CPU.

Record:- A collection of all the information pertaining to a particular entity instance.

Register:- A temporary storage unit for quick, direct. accessibility of a small amount of data for processing.

Remote Server:- A network computer that allows a user on the network from a distant location to access information.

Response Time:- The total time elapsed between submission of command and data to a computer and getting the result of computation.

Router:- A network device that enables the network to reroute messages it receives that are intended for The network with the router receives and sends it on its way exactly as received.

:- The process of choosing the best path throughout the LAN.


Scanner:- An electronic device that uses light-sensing equipment to scan paper images such as text, photos, illustrations and translate the images into signals that
the computer can then store, modify, or distribute.

Search Engine:- Software that makes it possible to look for and retrieve information on the Internet, particularly the Web. Some popular search engines are AltaVista, Google, HotBot, Yahoo., Web Crawler and Lycos. Sector A section of a recording track on a magnetic disk.

Sequential Access:- It is a class of data storage device that read stored data in a sequence.

Server:- A computer that shares its resources and information with other computers on a network.

Shareware:- A software that is not free but is available for a free trial period.

Shell:- It is an outer layer of a program that provides that user interface or the way of instruct the computer.

Simplex:- Transmission of data in one direction only.

:-The let of computer programs, procedure and associated documentation related to the effective operation.

Source Code:- (Source Program) A set of computer instructions in hard-copy or stored form.

Spreadsheet:- Software that allows one to calculate numbers in a format that is similar to pages in a conventional ledger.

Sub Program:- A particular part of a program that
complete the special work.

Super Computer The largest mainframe computer featuring exceptionally high speed operation while manipulating huge amounts of information.


TCP/IP:- Stands for Transmission Control Protocol/Internet Protocol. This is a large grouping of programs and standards that govern how information moves round the Internet.

Terabyte (TB):- It is about a trillion bytes. Actually it’s 2 or 10095111627776 bytes.

Terminal:- This is what you look at when you’re on the Internet. It’s your computer screen.

Time Sharing:- to the allocation of computer resources in a time dependent fashion to run several programs simultaneously.

Topology:- The structure of the network including physical connection such as wiring schemes and logical interactions between network devices.

Track:- A ring on the surface of a magnetic disk.

Trackball:- Input device that controls the position of the cursor on the screen.


Uniform Resource Locator:- (URL) The specific Internet address for a resource such as an individual or an organisation.

Unix:- This is an operating system developed by AT &
T. It is a big push that it allows one server to serve
many different end users at one time.

Upgrade:- The process of improve hardware and
software functionality.

Upload:- The processes of transferring information from a computer to a Website (or other remote location on a network).

UPS:- (Universal Power Supply or Uninterruptible Power Supply) An electrical power supply that includes a battery to provide enough power to a computer during an outage to back-up data and properly shut down.

User:- A person who uses or operate something.

User-Friendly:- A software program that has been designed to easily direct the user through the operation or application of a program.


Validation:- The process of making sure that the forms and documents from a particular transaction are correct.

Video Teleconferencing:- A remote face-to-face chat, when two or more people using a webcam and an Internet telephone connection chat online. The webcam enables both live voice and video.

Virus:- A piece of computer code designed as a prank or malicious act to spread from one computer to another by attaching itself to other programs.

Volatile Memory:- A memory whose contents are irretrievably lost when power is removed. If data in Ram must be saved after power shutdown, back-up in non-volatile memory (magnetic disk, tape, or Cd-R) is essential.


Window:-A portion of a computer display used in a graphical interface that enables users to select commands by pointing to illustrations or symbols with a mouse.

Wide Area Network:- It is a telecommunications network or computer network that extends over a large geographical distance.

Word Processor:- A computer system or program for setting, editing, revising, correcting, storing and printing text.

World Wide Web (‘WWW’ or ‘The Web’):- A network of servers on the Internet that use hypertext-linked databases and files. It was developed in 1989 by Tim Berners-Lee, a British computer scientist and is now
the primary platform of the Internet.

Workgroup:- Persons sharing files and data between themselves.

Workstation:- The work area and/or equipment used for computer operations, including computer-aided design (CAD). The equipment generally consists of a monitor, keyboard, printer and/or plotter and other output devices.


X-Y Plotter:- A computer-driven printing mechanism that draws coordinate points in graph form.


ZOOM:- The enlarging or reducing an image displayed on a computer process of proportionately monitor.

ZIP:- Stands for Zone Information Protocol. This is an application that allows for the compression of application files.

Zombie:- A computer that has been hijacked by a cracker without the owner knowledge and used to perform malicious tasks on the Internet.

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Pooja Rastogi

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