accommodative convergence/accommodation ratio
ac/hr aircraft per hour
ac2 audio An audio format, succeded by AC3. (2001-12-18)
ac3 audio An audio format by Sony[?], the successor of AC2. AC3 is used for multi-channel audio for digital video. (2001-12-18)
Agricultural Conservation and Adjustment Administration.
acaai American College of Allergy, Asthma, and Immunology