chiasma

noun

chi·​as·​ma kī-ˈaz-mə How to pronounce chiasma (audio)
kē-
plural chiasmata kī-ˈaz-mə-tə How to pronounce chiasma (audio)
kē-
1
: an anatomical intersection or decussation compare optic chiasma
2
: a cross-shaped configuration of paired chromatids visible in the diplotene stage of meiotic prophase and considered the cytological equivalent of genetic crossing-over
chiasmatic adjective

Word History

Etymology

New Latin, X-shaped configuration, from Greek, crosspiece, from chiazein to mark with a chi, from chi (x)

First Known Use

1839, in the meaning defined at sense 1

Time Traveler
The first known use of chiasma was in 1839

Dictionary Entries Near chiasma

Cite this Entry

“Chiasma.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/chiasma. Accessed 28 Mar. 2024.

Medical Definition

chiasma

noun
chi·​as·​ma kī-ˈaz-mə, kē- How to pronounce chiasma (audio)
plural chiasmata -mət-ə How to pronounce chiasma (audio)
1
: an anatomical intersection or decussation see optic chiasma
2
: a cross-shaped configuration of paired chromatids visible in the diplotene of meiotic prophase and considered the cytological equivalent of genetic crossing-over
chiasmatic adjective

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