To cherish with care.

To think anxiously or moodily upon.

Kept for breeding from; as, a brood mare; brood stock;
having young; as, a brood sow.

To sit over, cover, and cherish; as, a hen broods her
chickens.

To sit on and cover eggs, as a fowl, for the purpose of
warming them and hatching the young; or to sit over and cover young, as
a hen her chickens, in order to warm and protect them; hence, to sit
quietly, as if brooding.

Sitting or inclined to sit on eggs.

That which is bred or produced; breed; species.

The young birds hatched at one time; a hatch; as, a brood
of chickens.

Heavy waste in tin and copper ores.

To have the mind dwell continuously or moodily on a
subject; to think long and anxiously; to be in a state of gloomy,
serious thought; – usually followed by over or on; as, to brood over
misfortunes.