Green’s Dictionary of Slang

(W.I./UK black) music with or without vocals, invariably spiced up with snatches of echo and similar special effects, created by skilful, artistic re-engineering of recorded tracks; also attrib.

1983		C. Knight We Shall Not Die 59: The heavy dub sounds would be pouring from the crowded dance hall.
1995		Francis-Jackson Official Dancehall Dict. 16: Dub 1. heavy instrumental 2. type of dance characterised by slow pelvic crunching movements.
2000		Indep. Rev. 21 Jan. 15: A penchant for Jamaican dub and easy-listening Latin music.
2015		‘Elvis Costello’ Unfaithful Music 453: My first encounter of his performance was a dub mix of just Roy's voice and the Van Dyke Parks string arrangement.