/ Dictionary / Index A allantoid: Meaning and Definition of Find definitions for: al•lan•toid Pronunciation: (u-lan'toid), [key] — adj. allantoic. —n. the allantois. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: allantoid (Thesaurus) allantoic allantoin Related Content Daily Word Quiz: philanthropy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language