synapsid vs synapsid reptile

synapsid and synapsid reptile both are nouns.

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

As nouns, synapsid and synapsid reptile are synonyms defined as:

synapsid and synapsid reptile: extinct reptile having a single pair of lateral temporal openings in the skull

synapsid (noun)	synapsid reptile (noun)
extinct reptile having a single pair of lateral temporal openings in the skull	extinct reptile having a single pair of lateral temporal openings in the skull