(bit′ərn) noun
A small, speckled, pale-buff heron (Botaurus lentiginosus) of North America, which utters a booming note in the breeding season.
—least bittern The American dwarf bittern (Ixobrychus exilis). [<OF butor, ? <L butio, -onis a hawk]

(bit′ərn) noun
1. In salt manufacture, the waste liquor remaining after crystallization from brine.
2. A bitter mixture of quassia.