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 ]   audio   plural A’s or As in Western music, the sixth Take note in the size (= series of notes) that begins about the note C, or possibly a set of notes dependant on this ObserveWhen the ancient Greeks adopted the alphabet, they'd no use f