"sit on eggs, hatch," mid-15c., from brood (n.). The figurative meaning ("to incubate in the mind") is first recorded 1570s, from notion of "nursing" one's anger, re [..]

Old English brod "brood, fetus, hatchling," from Proto-Germanic *brod (source also of Middle Dutch broet, Old High German bruot, German Brut "brood"), literally "that which is [..]

Immature honey bees that have not yet emerged from their cells. Brood can be in the form of eggs, larvae, or pupae of different ages.

All the individuals of a generation that hatch at about the same time.

to sit quietly and think about something rather anxiously. The same word also means young birds all hatched in one nest at the same time

dumen

To see a fowl with her brood, denotes that, if you are a woman, your cares will be varied and irksome. Many children will be in your care, and some of them will prove wayward and unruly. Brood, to others, denotes accumulation of wealth.   

The young hatched from a clutch of eggs; a species of bird may have two or even three broods in a single breeding season.

The number of young produced or hatched at any one time.

(n) the young of an animal cared for at one time(v) think moodily or anxiously about something(v) hang over, as of something threatening, dark, or menacing(v) be in a huff and display one's displ [..]

noun: the offspring of a single birth or set of eggs, or any group of young that is being cared for together by an adult. verb: to incubate eggs.

A term for sitting on (eggs); "Birds brood"; "The female covers the eggs"

larval development of offspring takes place within a brood pouch

A single generation of butterflies, all of which fly during the same time period.

The young (as of a bird or insect) hatched or cared for all at one time.

Group of young. Some animals mate and have more than one brood in a year.

 the immatures that hatch from eggs laid by a single female at the same time.

the young of certain animals; in fire ants, the eggs, larvae and pupae make up the brood

A single generation of a population. Hence double-brooded refers to a species having 2 generations per year.

single generation of butterflies living during the same time period

a group of immature bees before they have emerged from their cells.