名詞 chiasma:

1. an intersection or crossing of two tracts in the form of the letter X
   同義詞：chiasm, decussation

chi.as.ma

n.（名詞）
【復數(shù)】 chi.as.ma.ta[-m…-t…] 或 chi.as.mas 也作 chi.asms
Anatomy A crossing or intersection of two tracts, as of nerves or ligaments.
【解剖學】 視神經(jīng)交叉：如神經(jīng)或韌帶等兩束相交或橫斷
Genetics The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over.
【遺傳學】 染色體交叉：在減數(shù)分裂過程中成對的染色體之間的接觸點產(chǎn)生一種交叉形狀的構(gòu)造，代表著基因互相交換的細胞表現(xiàn)形式

來源：
Greek khiasma [cross-piece]
希臘語 khiasma [橫桿]
from khiazein [to mark with an X]
源自 khiazein [用X作標記]
from khi [chi (from the letter`s shape)]
源自 khi [chi（來自字母X的形狀）]

【引伸】
chias.mal 或
chias.mic 或
chi.asmat.ic