/ Dictionary / Index O olein: Meaning and Definition of Find definitions for: o•le•in Pronunciation: (ō'lē-in), [key] — n. Chem. Also calleda colorless to yellowish, oily, water-insoluble liquid, CHO, the triglyceride of oleic acid, present in many vegetable oils. the oily or lower-melting fractions of a fat as distinguished from the solid or higher-melting constituents. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: olein (Thesaurus) oleiferous oleo Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language