GNU Collaborative International Dictionary of English

Found 2 definitions

1.       
   Ac n.
   the chemical symbol for actinum, a radioactive element.
   Syn. -- actinium
   WordNet 1.5
         
       

2.       
   AC n. [Acronym from alternating current.] an electric current that reverses direction sinusoidally.  Alternative to direct current, DC. [acron.] 
   Syn. -- alternating current 
   WordNet 1.5