Abbreviated for "Asian Boyz", an asian pacific gang around many areas of Massachussetts, Maine and California. They represent a royal blue bandana (rag or flag), as a trademark for their color. Also affiliated with the Crips, and also taunted with being called a "Crab", "Crab ass nigga", "Fuckin' Crab." Also can be represented in the numbers 1226.
Yo there be Clowny, that crab ass AB nigga.
He jus got his ass jumped into AB.