zygote vs fertilized ovum

zygote and fertilized ovum both are nouns.

Word	Noun	Adjective	Verb	Adverb
zygote	Yes	No	No	No
fertilized ovum	Yes	No	No	No

As nouns, zygote and fertilized ovum are synonyms defined as:

zygote and fertilized ovum: (genetics) the diploid cell resulting from the union of a haploid spermatozoon and ovum (including the organism that develops from that cell)

zygote (noun)	fertilized ovum (noun)
(genetics) the diploid cell resulting from the union of a haploid spermatozoon and ovum (including the organism that develops from that cell)	(genetics) the diploid cell resulting from the union of a haploid spermatozoon and ovum (including the organism that develops from that cell)