phrenic vein vs vena phrenica

phrenic vein and vena phrenica both are nouns.

Word	Noun	Adjective	Verb	Adverb
phrenic vein	Yes	No	No	No
vena phrenica	Yes	No	No	No

As nouns, phrenic vein and vena phrenica are synonyms defined as:

phrenic vein and vena phrenica: either of two veins that drain the diaphragm

phrenic vein (noun)	vena phrenica (noun)
either of two veins that drain the diaphragm	either of two veins that drain the diaphragm