noun, plural: oogonia
(zoology) The diploid female gametogonium that gives rise to primary oocyte through oocytogenesis.
(botany) The female reproductive structure in thallophytes (e.g. algae) that appear as rounded cells or sacs containing one or more oospheres.
In animals and humans, the oogonia are actually primordial germ cells that have migrated from the yolk sac to the genital ridge during the early embryonic stage. When the oogonia start meiosis they are now referred to as primary oocytes.
See also: secondary oocyte