Chiasma

Noun

1. A crossing of two nerves, ligaments etc.
2. The contact point between the two chromatids of a chromosome during meiosis.
3. An instance<!--countable--> of chiasmus<!--uncountable-->.<!--Wikipedia at [[w:chiasma]] agrees; this usage is arguably a mild catachresis for [[chiasm]] meant in that sense, but regardless, its existence is a fact descriptively.-->