/ Dictionary / Index A aloin: Meaning and Definition of Find definitions for: al•o•in Pronunciation: (al'ō-in), [key] — n. Pharm. an intensely bitter, crystalline, water-soluble powder composed of the active principles of and obtained from aloe, used chiefly as a purgative. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Aloidae alone Related Content Daily Word Quiz: respite Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language