/ Dictionary / Index I indolebutyric acid: Meaning and Definition of Find definitions for: in'dole•bu•tyr'ic ac'id Pronunciation: (in'dōl-by-tir'ik, in"-), [key] — Biochem. Biochem. a white or yellowish, crystalline, water-insoluble powder, CHON, a plant hormone similar to indoleacetic acid and used for the same purposes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. indoleacetic acid indolence Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language