Definify.com
Webster 1913 Edition
Chiasma
{
Chi′asm
(kī′ăz’m)
, ‖Chi-as′ma
(kī̍-ăz′mȧ)
, } Noun.
[NL.
chiasma
, fr. Gr. χίασμα
two lines placed crosswise, fr. [GREEK] to mark with a χ.] (Anat.)
A commissure; an intersection or crossing of two tracts; especially, the optic commissure, or crucial union of the optic nerves.
– Chi-as′mal
, Adj.