Biology term for the act of incubating eggs, especially by sitting on them or keeping them warm.
Brooding behavior in birds varies by species.
Compound of 介 (kai, 'to mediate' or 'to be between') and 卵 (ran, 'egg'), referring to the act of sitting on or caring for eggs. The exact historical derivation is uncertain; the spelling is conventionally associated with this meaning in biological contexts.