Meaning of destructive interference

destruc'tive interfer'ence

Pronunciation: [key]
— Physics. Physics.
  1. the interference of two waves of equal frequency and opposite phase, resulting in their cancellation where the negative displacement of one always coincides with the positive displacement of the other. Cf. constructive interference.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.