AC AC /eɪ si/

noun

1. An electric current that reverses direction sinusoidally  ( AC , alternating current , alternating electric current )
   an electric current that reverses direction sinusoidally
    In the US most household current is AC at 60 cycles per second
   In the US most household current is AC at 60 cycles per second
   
   

 Ac

1. A radioactive element of the actinide series; found in uranium ores  ( Ac , actinium , atomic number 89 )
   a radioactive element of the actinide series; found in uranium ores