access permissions See permissions.
accessibility The degree to which a device or program is usable by people with disabilities.
admin user An administrative user of Mac OS X; a user who can read, write, and move some files that do not belong to her and who can change locked System Preferences settings and install new software.
AIFF Audio Interchange File Format is a sound file format used by iMovie and other multimedia programs.
AirDrop A method of transferring files via Wi-Fi on an ad hoc basis, without setting up access permissions ahead of time.
AirPort An Apple-branded combination of hardware ...