/ Dictionary / Index O orthoboric acid: Meaning and Definition of Find definitions for: or'tho•bo'ric ac'id Pronunciation: (ôr'thu-bôr'ik, -bōr'-, ôr"thu-), [key] — Chem. Chem. See(def. 1). Cf.(def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ortho orthocenter Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language