/ Dictionary / Index A antheridium: Meaning and Definition of Find definitions for: an•ther•id•i•um Pronunciation: (an"thu-rid'ē-um), [key] — pl. -ther•id•i•a a male reproductive structure producing gametes, occurring in ferns, mosses, fungi, and algae. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: antheridium (Thesaurus) anther antherozoid Related Content Daily Word Quiz: nefarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language