Serial port - Socket at the back of a PC for connecting peripherals.

Taskbar - The taskbar, at the bottom of the screen, shows the programs in use.

Virus - A small, unauthorized program that can damage a PC.

Windows - An operating system used by the majority of PCs.

World Wide Web, WWW, the Web - WWW are initials that stand for World Wide Web. The Web is one of the services available on the Internet. It lets you access millions of pages through a system of links. Because it is 'world-wide', it was originally called the World Wide Web or WWW.