BITTERN

I. noun Etymology: Middle English bitoure, from Anglo-French butor, from Vulgar Latin *butitaurus, from Latin buteo hawk + taurus bull Date: 1515 any of various small or medium-sized usually secretive herons (especially genera Botaurus and Ixobrychus ), II. noun Etymology: irregular from 1bitter Date: 1682 the bitter water solution of salts that remains after sodium chloride has crystallized out of a brine