Green’s Dictionary of Slang

A.C. n.

[abbr.; note A.B. n. (3) and A.W. n.]

(US prison) Aryan Circle, a white supremacist prison gang.

[US]Other Side of the Wall: Prisoner’s Dict. July [Internet] AC: Aryan Circle, a white prison gang found in some states. This designation is not seen in California. More commonly in California, this designation would refer to the ‘Adjustment Center’.