To keep an egg warm to make it hatch.
In some species of birds, both the mother and father brood the eggs.
To protect (something that is gradually maturing); to foster.
Under the rock was a midshipman fish, brooding a mass of eggs.
(typically with about or over) To dwell upon moodily and at length, mainly alone.
He sat brooding about the upcoming battle, fearing the outcome.
To be bred.