>>279809864
CoA = Color of Armanent
CoO = Color of Observation
CoC = Color of Conquerors

A in front, like ACoC ? Advanced version of that Haki

ACoA = Ryuo, the internal destruction Haki Luffy learned in Udon
ACoO = Future Sight
ACoC = Conquerors Coating

Appearantly there's an even higher level of Advanced Conqurors Haki, which Gaban used to harm the God's Knights and bypass their regen.