AC
- .ac
- .ac (second-level domain)
- A. C. Grayling
- A. C. Green
- A. C. Newman
- A.C. Slater
- AC (complexity)
- AC Bonifacio
- AC Cars
- AC Comics
- AC Hotels
- AC Milan
- AC Restaurants
- AC Transit
- AC power
- AC – The Danish Confederation of Professional Associations
- AC/DC
- AC/DC (disambiguation)
- ACDelco
- Aachen
- Abkhazian Cup
- Ac (rune)
- Ace Combat
- Acetyl group
- Acre
- Acre (state)
- Acromioclavicular joint
- Actinium
- Action Congress of Nigeria
- Ad Council Japan
- Adenocarcinoma
- Adenylate cyclase
- Adriamycin
- Adult Contemporary (chart)
- Adult contemporary music
- Advisory Council on Youth
- Advisory circular
- After Christ
- After Colony
- Air Canada
- Air conditioning
- Aircraftman
- Al Cowlings
- Aleksandrovac
- Allergic conjunctivitis
- Allis-Chalmers
- Alternating current
- Alternative for Change
- Altocumulus cloud
- Anal Cunt
- Anderson, Clayton and Company
- Animal Crossing
- Anonymous;Code
- Ante Christum
- Anterior commissure
- Anterior cruciate ligament
- Anthrocon
- Antichrist
- Anticipated convection
- Antigua and Barbuda
- Appeal Cases
- Appropriateness criteria
- Ards Circuit
- Arithmetic coding
- Armor class
- Armored Core
- Army Corps
- Artificial consciousness
- Aryan Circle
- Asheron's Call
- Ashoka Chakra (military decoration)
- Asianovela Channel
- Asphalt concrete
- Assassin's Creed
- Assetto Corsa
- Assist control
- Assistant Commissioner of Police of the Metropolis
- Associated Content
- Astral Chain
- Athletics Canada
- Atlantic City, New Jersey
- Atlantic College
- Audit Commission (Hong Kong)
- Authorization certificate
- Average cost
- Aviation Cadet
- Axiom of choice
- Ayala Corporation
- Civic Alliance Foundation
- Coast Alliance
- First assistant camera
- Hydrogen cyanide
- IEEE 802.11ac-2013
- JPEG
- List of auxiliaries of the United States Navy
- Nut (hardware)
- Order of Australia
- Science Adventure
- Second assistant camera
- Senedd
- The Last Question