Definition of: oogonium

(ō′ə·gō′nē·əm) noun plural ·ni·a (-nē·ə)
1. Bot. The female reproductive organ in thallophytic plants, a large spherical cell or sac within which the oospheres, or egg cells, are developed.
2. Biol. A cell whose divisions give rise to oocytes. Also o·o·gone (ō′ə·gōn). [<NL <Gk. ōon an egg + gonos offspring]