All G&A a/c A/D a/r A/S a/s/l C/A See all meanings Idioms and phrases with a collision class idiom[ C/U ]   tunes   plural A’s or As in Western new music, the sixth note in the dimensions (= number of notes) that starts around the note C, or a set of notes based on this note[four] The Roman type ⟨a⟩ is located in most printed material, and