optic chiasma vs chiasma opticum

optic chiasma and chiasma opticum both are nouns.

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

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

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

Other synonyms of optic chiasma include optic chiasm.

optic chiasma (noun)	chiasma opticum (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