chiasma

noun

chi·​as·​ma kī-ˈaz-mə 

kē-

plural chiasmata kī-ˈaz-mə-tə 

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

ˌkī-əz-ˈma-tik 

ˌkē-

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

Phrases Containing chiasma

• optic chiasma

Medical Definition

chiasma

noun

chi·​as·​ma kī-ˈaz-mə, kē- 

plural chiasmata -mət-ə 

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

ˌkī-əz-ˈmat-ik, ˌkē- 

adjective