lie detector: Meaning and Definition of

lie' detec"tor

Pronunciation: [key]
  1. a polygraph used to determine changes in certain body activities, as blood pressure, pulse, breathing, and perspiration, the results of which may be interpreted to indicate the truth or falsity of a person's answers under questioning.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.