Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- The cell created by the union of two gametes, in which the gamete nuclei are also fused. The earliest stage of the diploid generation.
Glossary of "Evolution of Plants (2nd ed.)" by Willis & McElwain (2014)
- The diploid cell resulting from the fusion of the male and female gametes.
Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- The cell that results from sexual fusion of two gametes, commonly egg and sperm.
- 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.
- Willis, K. J. & McElwain, J. C. 2014. The Evolution of Plants, 2nd ed. -ix + 398 pp. Oxford University Press, Oxford.