/ Dictionary / Index R rein: Meaning and Definition of Find definitions for: rein Pronunciation: (rān), [key] —v.t. to check or guide (a horse or other animal) by exerting pressure on a bridle bit by means of the reins. to curb; restrain; control. —v.i. to obey the reins: a horse that reins well. to rein a horse or other animal. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: rein (Thesaurus) Reims reincarnate Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language