The American Heritage® Dictionary of the English Language, 4th Edition
adj. Of or for a four-channel sound system in which speakers are positioned at all four corners of the listening space, reproducing signals that are independent of each other.
adj. Employing four independent channels or speakers.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. of or relating to quadraphony
Word Usage
"The Xplore Wrangler certainly feels authentic on the highway, with quadraphonic tire roar blasting from the BFGs' deep treads and a serious lack of top speed, thanks to the vehicle's aerodynamics."