The cell formed by the union of two gametes, especially a fertilized ovum before cleavage.(noun)
The organism that develops from a zygote.(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.
Use "zygote" in a sentence
"The zygote is the first stage of development of an individual human being."
"A fertilised zygote is no more a person than an acorn is an oak tree."
"I certainly respect your points, anonymous ... but not everybody believes the way you do that a three-celled zygote is akin to an infant."