/ Dictionary / Index R reactive: Meaning and Definition of Find definitions for: re•ac•tive Pronunciation: (rē-ak'tiv), [key] — adj. tending to react. pertaining to or characterized by reaction. pertaining to or characterized by reactance. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: reactive (Thesaurus) reactivate reactive component Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language