optic chiasm vs optic chiasma

optic chiasm and optic chiasma both are nouns.

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

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

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

Other synonyms of optic chiasm include chiasma opticum.

optic chiasm (noun)	optic chiasma (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