n., pl., -ma·ta (-mə-tə), or -mas, also -asms.
- Anatomy. A crossing or intersection of two tracts, as of nerves or ligaments.
- Genetics. The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over.
[Greek khīasma, cross-piece, from khīazein, to mark with an X, from khei, khī, chi (from the letter's shape).]
chiasmal chi·as'mal or chi·as'mic or chi'as·mat'ic (-măt'ĭk) adj.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
