- a large marsh bird of the heron family, typically smaller than a heron, with brown streaked plumage. The larger kinds are noted for the deep booming call of the male in the breeding season.
- Genera Botaurus and Ixobrychus, family Ardeidae: several species, especially the American bittern (B. lentiginosus) and the least bittern (I. exilis)
late Middle English bitore, from Old French butor, based on Latin butio 'bittern' + taurus 'bull' (because of its call). The -n was added in the 16th century, perhaps by association with hern, obsolete variant of heron