All G&A a/c A/D a/r A/S a/s/l C/A See all meanings Idioms and phrases on the collision study course idiom[ C/U ]   tunes   plural A’s or As in Western music, the sixth note in the dimensions (= series of notes) that begins over the Notice C, or perhaps a set of notes according to this Observe?a? may be the third-most-commonly used letter in Eng