/ Dictionary / Index P primordium: Meaning and Definition of Find definitions for: pri•mor•di•um Pronunciation: (prī-môr'dē-um), [key] — pl. -di•a the first recognizable, histologically differentiated stage in the development of an organ. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: primordium (Thesaurus) primordial soup primp Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language