Definition of "oogonium" [‖O•ö•go•ni•um]

• A cell that arises from a primordial germ cell and differentiates into an oocyte in the ovary. (noun)
• A female reproductive structure in certain thallophytes, usually a rounded cell or sac containing one or more oospheres. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The female reproductive structure (oogonium) of a charophyte."
• "The formation of these follows the same course as that above described for the polysporic oogonium, with certain necessary simplifications."
• "Antheridia clavate, one, or rarely more, on each oogonium, usually arising just below its basal wall, rarely of diclinous origin."