Action Center The pop-up pane that appears when you click Notifications in the Windows taskbar; it displays system messages and quick links to key Windows functions.
add-in board A device that plugs into a desktop computer’s system unit and provides auxiliary functions. (Also called a card.)
all-in-one computer A desktop computer in which the system unit, monitor, and speakers are housed in a single unit. Often the monitor of such a system has a touchscreen display.
app See application.
application A computer program designed for a specific task or use, such as word processing, ...