Glossary

The Undo command is located in the Edit menu of most programs and has the shortcut "Ctrl+Z" (PC) or "Cmd-Z" (Mac). It is used to undo the most recent action performed in a program. Common events that can be undone include typing or deleting text in a word processing program, drawing or moving images in an image editor, and trimming media in a video or audio editing program. By selecting "Undo," most actions can be quickly reversed. Many programs also support "multiple undo," which makes it possible to undo several actions at once.

A very powerful operating system used as the basis of many high-end computer applications.

Uniform Resource Locator.

• The protocol for identifying a document on the Web.
• A Web address (e.g., www.tutorialspoint.com). A URL is unique to each user. See also domain.

A multiple-socket USB connector that allows several USB-compatible devices to be connected to a computer.

A user interface is the means in which a user controls a software program or hardware device. For example, a software interface may include windows, icons, menus, and buttons that allow the user to interact with the program. This is also known as a graphical user interface, or GUI. A hardware interface can be a remote control or a video game controller. It may also refer to the controls on a camcorder, digital camera, or iPod. Most modern user interfaces today are designed using a combination of hardware and software. 

A username is a name that uniquely identifies someone on a computer system. For example, a computer may be setup with multiple accounts, with different usernames for each account. Many websites allow users to choose a username so that they can customize their settings or set up an online account. For example, your bank may allow you to choose a username for accessing your banking information. You may need to choose a username in order to post messages to a certain message board on the Web. E-mail services, such as Hotmail require users to choose a username in order to use the service.

A username is almost always paired with a password. This username/password combination is referred to as a login, and is often required for users to log in to websites. For example, to access your e-mail via the Web, you are required to enter your username and password. Once you have logged in, your username may appear on the screen, but your password is kept secret. By keeping their password private, people can create secure accounts for various websites. Most usernames can contain letters and numbers, but no spaces. When you choose a username for an e-mail account, the part before the "@" is your username.

Utility programs, commonly referred to as just "utilities," are software programs that add functionality to your computer or help your computer perform better. These include antivirus, backup, disk repair, file management, security, and networking programs. Utilities can also be applications such as screensavers, font and icon tools, and desktop enhancements. Some utility programs help keep your computer free from unwanted software such as viruses or spyware, while others add functionality that allows you to customize your desktop and user interface. In general, programs that help make your computer better are considered utilities. And unlike water and electric bills, computer utilities don't send you a bill every month!