- 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 of chiasmaModern Latin from Classical Greek chiasma, a crosspiece from chiasmos, placing crosswise from chiazein, to mark with a chi (?)
nounpl. chi·as·ma·ta, 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 of chiasmaGreek khīasma cross-piece from khīazein to mark with an X from khei, khī chi (from the letter's shape)
- chi·as′mal chi·as′mic chi′as·mat′ic
(plural chiasmas or chiasmata)
Modern Latin, from Ancient Greek χίασμα (khiasma), from χίαζειν (khiazein, “to mark with the letter chi”).