chiasma
[kahy-az-muh]
- Anatomy. a crossing or decussation, as that of the optic nerves at the base of the brain.
- Cell Biology. a point of overlap of paired chromatids at which fusion and exchange of genetic material take place during prophase of meiosis.
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Also chi·asm [kahy-az-uh m] /ˈkaɪ æz əm/.
Origin of chiasma
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
chiasma
chiasm (ˈkaɪæzəm)
- cytology the cross-shaped connection produced by the crossing over of pairing chromosomes during meiosis
- anatomy the crossing over of two parts or structures, such as the fibres of the optic nerves in the brain
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Word Origin for chiasma
C19: from Greek khiasma wooden crosspiece, from khiazein to mark with an X, from khi chi 1
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for chiasmic
chiasma
"a crossing," 1832, medical Latin, from Greek khiasma "two things placed crosswise," which is related to khiasmos (see chiasmus). In cytology from 1911.
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Online Etymology Dictionary, © 2010 Douglas Harper
chiasma
(kī-ăz′mə)- A crossing or intersection of two tracts, as of nerves or ligaments.
- The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over.
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The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.