Merriam-Webster's Collegiate® Dictionary, 11th Edition
BROOD
I. noun see: barm Date: before 12th century the young of an animal or a family of young, a group having a common nature or origin, the children of a family,
II. adjective
Date: 15th century
kept for breeding ,
III. verb
Date: 15th century
transitive verb
1. to sit on or incubate (eggs), to produce by or as if by incubation ; hatch , to cover (young) with the wings, to think anxiously or gloomily about ; ponder , intransitive verb
1. to brood eggs or young, to sit quietly and thoughtfully ; meditate , hover , loom ,
3. to dwell gloomily on a subject, to be in a state of depression, broodingly adverb