add-in board A device that plugs in to a desktop computer’s system unit and provides auxiliary functions. (Also called a card.)
all-in-one computer A desktop computer where the system unit, monitor, and speakers are housed in a single unit. Often the monitor of such a system has s touchscreen display.
app See application.
application A computer program designed for a specific task or use, such as word processing, accounting, or missile guidance.
attachment A file, such as a Word document or graphics image, attached to an email message.
backup A copy of important data files.