AC

AC or Ac may refer to:

• Air conditioner, a machine that produces cool air
• Air conditioning, the mechanical process of cooling air in enclosed spaces
• Anarcho-capitalism, a form of free-market anarchism
• Ante Christum or A.C., a Latin term meaning "before Christ"
• Anthrocon, the largest furry convention in the world held in Pittsburgh, Pennsylvania
• Assessment center, a process to evaluate candidates for a job
• Average cost, in economics
• Acre, a unit of area with the symbol ac