chiasma opticum vs optic chiasm

chiasma opticum and optic chiasm both are nouns.

Word	Noun	Adjective	Verb	Adverb
chiasma opticum	Yes	No	No	No
optic chiasm	Yes	No	No	No

As nouns, chiasma opticum and optic chiasm are synonyms defined as:

chiasma opticum and optic chiasm: the crossing of the optic nerves from the two eyes at the base of the brain

Other synonyms of chiasma opticum include optic chiasma.

chiasma opticum (noun)	optic chiasm (noun)
the crossing of the optic nerves from the two eyes at the base of the brain	the crossing of the optic nerves from the two eyes at the base of the brain