an·ti·noise 
(ăn′tē-noiz, ăn′tī-)
(ăn′tē-noiz, ăn′tī-)adj.
1. Designed to reduce environmental noise, as in a community: an antinoise ordinance.
2. Capable of neutralizing the sound of another noise.
n.
A technique for neutralizing unwanted sound, in which a second sound wave, identical to but out of phase with the unwanted sound, is used to cancel the unwanted sound.