bittern 1
/bit"euhrn/ , n.
1. any of several tawny brown herons that inhabit reedy marshes, as Botaurus lentiginosus (American bittern) , of North America, and B. stellaris, of Europe.
2. any of several small herons of the genus Ixobrychus, as I. exilis (least bittern) , of temperate and tropical North and South America.
[ 1510-20; bitter, bittor bittern + -n (perh. by assoc. with HERON), ME bito ( u ) r, butur, boto ( u ) r bytore, AF, OF butor *butitaurus, equiv. to *buti-, perh. to be identified with L buteo a species of hawk (see BUTEO) + L taurus bull (cited by Pliny as a name for a bird emitting a bellowing sound) ]
bittern 2
/bit"euhrn/ , n. Chem.
a bitter solution remaining in salt making after the salt has crystallized out of seawater or brine, used as a source of bromides, iodides, and certain other salts.
[ 1675-85; var. of bittering; see BITTER, -ING 1 ]