sinus rectus vs tentorial sinus

sinus rectus and tentorial sinus both are nouns.

Word	Noun	Adjective	Verb	Adverb
sinus rectus	Yes	No	No	No
tentorial sinus	Yes	No	No	No

As nouns, sinus rectus and tentorial sinus are synonyms defined as:

Other synonyms of sinus rectus include straight sinus.

sinus rectus (noun)	tentorial sinus (noun)
an unpaired sinus of the dura mater	an unpaired sinus of the dura mater