/ Dictionary / Index T tricostate: Meaning and Definition of Find definitions for: tri•cos•tate Pronunciation: (trī-kos'tāt, -kô'stāt), [key] — adj. Bot., Zool. having three ribs, costae, or raised lines. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tricornered tricot Related Content Daily Word Quiz: lyre Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language