Chiasm \Chi"asm\, Chiasma \Chi*as"ma\, n. [NL. chiasma, fr. Gr.
? two lines placed crosswise, fr. ? to mark with a [chi].]
(Anat.)
A commissure; especially, the optic commissure, or crucial
union of the optic nerves. -- {Chi*as"mal}, a..
chiasmal
adj : of or relating to a chiasm [syn: {chiasmic}, {chiasmatic}]