- 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 kh&imacron;asma, cross-piece, from kh&imacron;azein, to mark with an X, from khei, kh&imacron;, 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”).