A police car. The red lights on old cop cars looked like a berry on top of an ice cream. "Berry flashing those high beams" refers to a cop behind your car signalling for you to pull over.
"Once I make this drug deal, man I'll be loaded! I'll be rollin' through town in Hummers and Benzs within a week motherfucker!"
"Fool the only car you're gonna be rollin' thru town in is a BERRY! That guy you're selling to is a cop."
short form of blackberrya fruit.
also a berry is a nicer name for a freak or a person that you are unable to put a label on. a person who dresses like a goth, emo, punk rocker