ovary vs reproductive structure

ovary and reproductive structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
ovary	Yes	No	No	No
reproductive structure	Yes	No	No	No

As nouns, reproductive structure is a hypernym of ovary; that is, reproductive structure is a word with a broader meaning than ovary:

ovary (noun)	reproductive structure (noun)
(vertebrates) one of usually two organs that produce ova and secrete estrogen and progesterone	the parts of a plant involved in its reproduction
the organ that bears the ovules of a flower