/ Dictionary / Index I isobutylene: Meaning and Definition of Find definitions for: i•so•bu•tyl•ene Pronunciation: (ī"su-byt'l-ēn"), [key] — n. Chem. a colorless, very volatile liquid or flammable gas, CH, used chiefly in the manufacture of butyl rubber. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: isobutylene (Thesaurus) isobutane isobutyl nitrite Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language