MAC has several meanings, including:

• MAC (cosmetics)
• (erroneously) Macintosh computer by Apple
• Mammalian artificial chromosome
• mandatory access control
• Maximum allowable concentration of toxins, e.g. in food or as reference in environmental remediation
• Media Access Control - hence MAC address
• Merchant Aircraft Carrier ships
• Message authentication code, in cryptography
• Metropolitan Airports Commission, operator of airports in the Minneapolis-St. Paul region of Minnesota
• Mid-American Conference, US collegiate sports conference
• Middle Atlantic Conference , US collegiate sports conference, also its parent group, the Middle Atlantic Corporation
• The Midlands Arts Centre, a venue in Birmingham, England
• Minimum alveolar concentration (Anaesthesia)
• Michigan Agricultural College, usually written "M.A.C.", was the name of Michigan State University from 1909 to 1925.
• Multiply-accumulate, especially in digital signal processor contexts
• MAC times in a computer file system are times of last modification, access, and change of a file.
• Michigan Aerospace Corporation , a company in Ann Arbor, Michigan.

See also: Mac.