Definition from Wiktionary, the free dictionary
See also Appendix:Variations of "ac"
- absolute ceiling
- account current
- (music) adult contemporary, a radio format
- air conditioning; air conditioned, usually: A/C
- air corps
- all clear, as in button on electronic calculator
- (electricity) alternating current; often used to indicate an alternating potential rather than a current, as in 110V AC.
- anno Christi, in the year of Christ.
- ante Christum before Christ.
- (medicine) ante cibum before meals.
- (religion) antichristian
- appellation contrôlée
- area code
- army corps
- (law) as charged, as in: guilty as charged, usually: a/c
- athletic club
- (Internet, slang) audible chuckle
- author's correction
- automobile club
- (US, military) Auxiliary Collier - a naval coal transport that travels with the fleet to provide coal for coal powered warships
- (set theory) axiom of choice
- (Australia) Companion of the Order of Australia.
- aviation cadet
Derived terms 
- Acre (Brazilian state)