chiasma

(kī az′mə)

noun pl. chiasmata

a crossing or intersection of the optic nerves in the hypothalamus of the brain
a point of contact between chromosomes during meiosis where two chromatids interchange corresponding segments
any crosswise function

Origin: ModL < Gr chiasma, a crosspiece < chiasmos, placing crosswise < chiazein, to mark with a chi (χ)

See chiasma in American Heritage Dictionary 4

noun pl. chi·as·ma·ta (-mə-tə) or chi·as·mas also chi·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.

Origin:

Origin: Greek khīasma, cross-piece

Origin: , from khīazein, to mark with an X

Origin: , from khei, khī, chi (from the letter's shape)

Related Forms: