Dictionary
pri•mor•di•um
Pronunciation: (prī-môr'dē-um), [key]—
n.,
—pl. -di•aPronunciation: (-dē-u). [key]
Embryol.
the first recognizable, histologically differentiated stage in the development of an organ.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.