Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- A female gamete, usually non-motile and larger than the corresponding male gamete (sperm).
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- In all sexually reproducing organisms, the female gamete; in birds, reptiles, and some other vertebrates, a structure within which early embryonic development occurs. See also amniote egg, ovum.
Glossary of Plant Systematics (1st ed.) by Simpson (2006)
- A nonmotile, evolutionarily enlarged gamete, the end product of oogamy.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.
- Simpson, M. G. 2006. Plant Systematics. -xi + 590 pp. Elsevier Academic Press, Oxford.