Also found in: Medical, Encyclopedia, Wikipedia.


n. pl. o·o·go·ni·a (-nē-ə) or o·o·go·ni·ums
1. Any of the cells that give rise through mitosis to the oocytes and are found in the ovaries of vertebrates.
2. A female reproductive structure in certain thallophytes and in oomycetes, usually a rounded cell or sac containing one or more oospheres.

[oo- + New Latin gonium, cell (from Greek gonos, seed; see gono-).]

o′o·go′ni·al (-nē-əl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


n, pl -nia (-nɪə) or -niums
1. (Biology) an immature female germ cell forming oocytes by repeated divisions
2. (Botany) a female sex organ of some algae and fungi producing female gametes (oospheres)
ooˈgonial adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌoʊ əˈgoʊ ni əm)

n., pl. -ni•a (-ni ə) -ni•ums.
1. one of the undifferentiated germ cells giving rise to oocytes.
2. the one-celled female reproductive organ in certain fungi, usu. a spherical sac containing one or more eggs.
o`o•go′ni•al, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
Mentioned in ?
References in periodicals archive ?
The DUSP4 protein was essential in the process of endoderm generating spermatogonium or oogonium (Brown et al., 2008).
CA, cortical alveoli; AF, atretic follicle; BM, basement membrane; F, follicle cell; FG, full-grown oocyte; LO, leptotene oocytes; N, nucleus; NU, perinuclear nucleoli; OF, ovarian follicle; OG, oogonium; OL, ovarian lumen; PF, prefollicle cells; PG, primary growth oocyte; PO, pachytene oocyte; SG, secondary growth oocyte; Y, yolk globule; ZP, zona pellucida.
In order for primordial follicle formation to occur, the germ cell cyst must break down and the oogonium be enveloped in a single-cell layer membrane.
Oogonium contains a relatively large nucleus (8.0 [micro]m) with a conspicuous nuclear membrane and characterized by only a single eccentrally located nucleolus as shown in Fig.(3, b, d & f|).
There are 5 ovarian stages during the ovarian development cycle: stage I, before puberty molting and with a triangular pleonal flap, with the ovary mainly include oogonium; stage II, the ovary is milky white and comprised mainly of previtellogenic oocytes and endogenous vitellogenic oocytes; stage III, the ovary is light yellow or tan and comprised primarily of exogenous vitellogenic oocytes and endogenous vitellogenic oocytes; stage IV, the ovary is deep purple and comprised mainly of nearly mature oocytes and exogenous vitellogenic oocytes; and stage V: the ovary is chocolate brown and comprised mainly of mature oocytes.
In humans, primordial germ cells or oogonium are the first stage of development into ovums, or mature eggs.