/ Dictionary / Index R reaction time: Meaning and Definition of Find definitions for: reac'tion time" Pronunciation: [key] — Psychol. Psychol. the interval between stimulation and response. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. reaction formation reaction turbine Related Content Daily Word Quiz: diligent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language