The term chiasma comes from the Greek χίασμα, which is related to the Greek letter Χ and means "crossing". It has a number of related meanings in biology. The plural is chiasmata.

• It is sometimes used to refer to the optic chiasm.
• More generally, in anatomy, it refers to the point where two (or more) nerves or ligaments cross or intersect.
• In genetics, it describes the point where two chromatids are intertwined (interwoven) in a cell: see chiasma (genetics).