1Bee-keeping. A group of brood cells in a honeycomb.

2An area of bare, flaccid skin containing numerous blood vessels which is present on the underside of certain birds during the nesting season and is used to transfer heat to the eggs during incubation.

3An area of specialized skin on the underside of males of certain syngnathid fishes, especially pipefishes and sea dragons, onto which the female deposits eggs.