Leto vs Greco-Roman deity

Leto and Greco-Roman deity both are nouns.

Word	Noun	Adjective	Verb	Adverb
Leto	Yes	No	No	No
Greco-Roman deity	Yes	No	No	No

As nouns, Greco-Roman deity is a hypernym of Leto; that is, Greco-Roman deity is a word with a broader meaning than Leto:

Leto: wife or mistress of Zeus and mother of Apollo and Artemis in ancient mythology; called Latona in Roman mythology
Greco-Roman deity: a deity of classical mythology

Other hypernyms of Leto include Graeco-Roman deity.

Leto (noun)	Greco-Roman deity (noun)
wife or mistress of Zeus and mother of Apollo and Artemis in ancient mythology; called Latona in Roman mythology	a deity of classical mythology