{ ‖ } n. [ NL. chiasma, fr. Gr. chi`asma two lines placed crosswise, fr. &unr_; 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 a.. [1913 Webster]

adj. of or pertaining to a chiasma. [ WordNet 1.5 ]

‖n. [ NL., fr. Gr. chiasmo`s a placing crosswise, fr. chia`zein. See Chiasm. ] (Rhet.) An inversion of the order of words or phrases, when repeated or subsequently referred to in a sentence; thus, [ 1913 Webster ]

If e'er to bless thy sons
My voice or hands deny,
These hands let useful skill forsake,
This voice in silence die. Dwight. [ 1913 Webster ]