synapsid vs therapsid

synapsid and therapsid both are nouns.

Word	Noun	Adjective	Verb	Adverb
synapsid	Yes	No	No	No
therapsid	Yes	No	No	No

As nouns, therapsid is a hyponym of synapsid; that is, therapsid is a word with a more specific, narrower meaning than synapsid:

synapsid: extinct reptile having a single pair of lateral temporal openings in the skull
therapsid: probably warm-blooded; considered direct ancestor of mammals

Other hyponyms of synapsid include protomammal, ictodosaur, pelycosaur, edaphosaurus, dimetrodon.

synapsid (noun)	therapsid (noun)
extinct reptile having a single pair of lateral temporal openings in the skull	probably warm-blooded; considered direct ancestor of mammals