/ Dictionary / Index T triethyl orthoformate: Meaning and Definition of Find definitions for: trieth'yl orthofor'mate Pronunciation: [key] — Chem. Chem. a colorless liquid, CHO, used chiefly in organic synthesis. Also called aethon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. triethylamine trifacial Related Content Daily Word Quiz: sinister Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language