Computer Terms A-Z
Use this glossary to look up unfamiliar computer terms. Click on any letter to jump to that section, or use Ctrl+F to search for a specific term.
A
Application
A program or piece of software that performs a specific task, such as a word processor, web browser, or spreadsheet program. Also called an "app" or "software program."
Attachment
A file that is sent along with an email message. Common attachments include documents, images, and PDFs.
B
Backup
A copy of your important files that you save in case the original files are lost or damaged. Backups should be made regularly to prevent data loss.
Browser
A program used to view websites on the internet. Popular browsers include Internet Explorer, Firefox, Chrome, and Safari.
Byte
A unit of data storage. One byte holds one character of text. A kilobyte (KB) is 1,024 bytes, a megabyte (MB) is about 1 million bytes.
C
Cache
A temporary storage area where frequently accessed data is stored for quicker access. Browsers cache web pages to load them faster on repeat visits.
Click
To press and release a mouse button. A single click (left button) selects items; a right-click shows a menu of options.
Cloud
Online storage services where you can save files and access them from any device with internet. Examples include Google Drive and Dropbox.
Cookies
Small text files that websites store on your computer to remember information about you, such as login status or preferences.
Cursor
The small arrow or pointer on your screen that moves when you move your mouse. It shows where your next action will happen.
D
Desktop
The main screen area of your computer showing icons, wallpaper, and the taskbar. Also refers to a type of computer that sits on a desk.
Download
To copy a file from the internet to your computer. The opposite of upload.
Drag
To hold down the mouse button while moving the mouse, which moves an item on screen. Used to move files or select text.
Driver
A program that lets your computer communicate with a specific piece of hardware, like a printer or scanner.
E
Email
Electronic mail - messages sent over the internet from one person to another. Examples include Gmail, Yahoo Mail, and Outlook.
Extension
The letters after the dot in a filename (like .doc or .jpg) that indicate what type of file it is.
F
File
A document, image, or other piece of information stored on your computer. Files have names and extensions.
Folder
A container on your computer used to organize and group files. Similar to a physical folder in a filing cabinet.
Firefox
A popular web browser made by Mozilla. It's free to download and known for its speed and security features.
Firmware
Software that is permanently installed in hardware devices, such as the basic input/output system (BIOS) in a computer.
G
GB (Gigabyte)
A unit of data storage equal to about 1 billion bytes. Modern computers typically have hundreds of gigabytes of storage.
Google
A popular search engine company that also offers email (Gmail), cloud storage (Google Drive), and many other internet services.
H
Hard Drive
The main storage device in your computer where files, programs, and the operating system are stored. Also called a "hard disk."
Hardware
The physical parts of a computer you can touch, such as the monitor, keyboard, mouse, and tower. The opposite of software.
Homepage
The main or starting page of a website. Also refers to the page your browser shows when you open it.
I
Icon
A small picture or symbol on your screen that represents a program, file, or function. Double-click an icon to open it.
Internet
The worldwide network of connected computers that allows people to share information and communicate. The internet is accessed through web browsers.
J
JPEG
A common image file format. Photos from digital cameras are often saved as JPEG files. The extension is .jpg or .jpeg.
K
KB (Kilobyte)
A unit of data storage equal to 1,024 bytes. A typical text document is only a few kilobytes.
Keyboard
The input device with keys for typing letters, numbers, and symbols. Combined with the mouse for computer control.
L
Laptop
A portable computer that folds up for easy carrying. Also called a "notebook" computer.
Link
Text or an image on a webpage that you can click to go to another page. Also called a "hyperlink" or "web link."
Login
To enter your username and password to access a computer system or website. Also used as a noun for your login credentials.
M
MB (Megabyte)
A unit of data storage equal to about 1 million bytes. A typical MP3 song is about 3-5 megabytes.
Menu
A list of options that appears when you click on something, showing available actions or settings.
Monitor
The screen display that shows your computer's output. Also called a "display" or "screen."
Motherboard
The main circuit board inside your computer that connects all the components together.
Mouse
The handheld device that controls the cursor on screen. Used to point, click, and drag items.
N
Network
Two or more computers connected together to share files and resources. The internet is a global network.
NIC (Network Interface Card)
The hardware component that allows a computer to connect to a network, including the internet.
O
Operating System
The main software that runs your computer and manages all other programs. Examples include Windows, Mac OS, and Linux.
Outlook
Microsoft's email and calendar program, part of the Microsoft Office suite. Also called Microsoft Outlook.
P
Password
A secret string of characters used to log into your computer or accounts. Should be kept private and changed regularly.
PDF
Portable Document Format - a file type that preserves formatting across different computers. Common for sharing documents.
Phishing
A type of scam where criminals try to trick you into revealing personal information by pretending to be a trusted company.
Pixel
The smallest unit of a digital image. Screens are made up of thousands of pixels arranged in a grid.
Plug-in
A small program that adds extra features to your web browser, such as Flash for animations or PDF viewers.
Pop-up
A small window that suddenly appears over or under the webpage you're viewing, often for advertising.
Port
A connection point on a computer where you plug in devices like printers, cameras, or USB drives.
Processor
The main chip that runs programs and calculations. Also called the CPU (Central Processing Unit) or "brain" of the computer.
R
RAM (Random Access Memory)
Your computer's temporary working memory. More RAM allows your computer to run more programs at once without slowing down.
Reboot
To restart your computer. This can fix many common problems by clearing temporary memory.
Right-click
To click the right mouse button, which usually shows a menu of options for the item you clicked.
S
Safari
The web browser made by Apple, included on Mac computers and iPhones. Known for its speed and simplicity.
Scroll
To move up or down through a webpage or document. Use the scroll bar, mouse wheel, or arrow keys.
Search Engine
A website like Google, Bing, or Yahoo that helps you find information on the internet by searching for keywords.
Shortcut
A quick way to open a program or file. Desktop shortcuts are icons that double-click to launch an application.
Software
Programs and applications that run on your computer. The instructions that tell hardware what to do. Opposite of hardware.
Spam
Unwanted email messages, usually advertising. Keep your email address private to reduce spam.
Start Menu
The menu in Windows that appears when you click the Start button, giving access to programs, settings, and shutdown options.
T
Taskbar
The bar at the bottom of your Windows screen showing open programs and the system clock. Quick access to running applications.
Toolbar
A row of buttons in a program that provides quick access to common commands, usually just above the document area.
Trojan
A type of malware disguised as a legitimate program but actually contains harmful code. Named after the Trojan horse.
U
Upload
To send a file from your computer to the internet, such as posting photos to a website. Opposite of download.
URL
Uniform Resource Locator - the address of a webpage, like www.learnmycomputer.org. You type it in your browser's address bar.
USB
Universal Serial Bus - a standard type of connection for attaching devices like printers, cameras, and storage drives.
V
Virus
A harmful program that can copy itself and spread from computer to computer, often causing damage or stealing information.
W
Web
Short for "World Wide Web" - the system of interconnected pages and documents accessed through the internet.
Website
A collection of related web pages on a particular topic, accessible at a single URL. For example, www.learnmycomputer.org.
Wi-Fi
A wireless technology that allows devices to connect to the internet without physical cables. Common in homes and businesses.
Windows
Microsoft's operating system. Versions include Windows XP, Vista, Windows 7, and Windows 8. The most common PC operating system.
Word Processor
A program for creating and editing text documents. Microsoft Word is the most popular example.
X
XML
Extensible Markup Language - a format for structuring data used in web applications and data exchange.
Y
Yahoo
A popular internet company offering email, news, search, and other web services.
Z
Zip
A compressed file format that reduces file size for storage or sending. Also used as a verb meaning to compress files.