foramen vs hiatus

foramen and hiatus both are nouns.

Word	Noun	Adjective	Verb	Adverb
foramen	Yes	No	No	No
hiatus	Yes	No	No	No

As nouns, foramen and hiatus are synonyms defined as:

foramen and hiatus: a natural opening or perforation through a bone or a membranous structure

foramen (noun)	hiatus (noun)
a natural opening or perforation through a bone or a membranous structure	a natural opening or perforation through a bone or a membranous structure
	a missing piece (as a gap in a manuscript)
	an interruption in the intensity or amount of something