• WordNet 3.6
    • n chiasma an intersection or crossing of two tracts in the form of the letter X
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Webster's Revised Unabridged Dictionary
    • n Chiasma (Anat) A commissure; an intersection or crossing of two tracts; especially, the optic commissure, or crucial union of the optic nerves.
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Century Dictionary and Cyclopedia
    • n chiasma Same as chiasm.
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Webster's Revised Unabridged Dictionary
NL. chiasma, fr. Gr. chi`asma two lines placed crosswise, fr. to mark with a χ


In literature:

We know that they are directly connected by fibres that arch round through the chiasma.
"Medical Essays" by Oliver Wendell Holmes, Sr.
Chiasma: an X-like crossing of nerve fibers.
"Explanation of Terms Used in Entomology" by John. B. Smith
The nerves are fibrous, and a commencement of the chiasma is certainly present.
"The Works of Francis Maitland Balfour, Volume 1" by Francis Maitland Balfour