Is it ensure, insure, or assure?
heron-like bird, 13c., botor, from Old French butor "bittern," perhaps from Gallo-Romance *butitaurus, from Latin butionem "bittern" + taurus "bull" (see steer (n.)); according to Pliny, so called because of its booming voice, but this seems fanciful. Modern form from 1510s.
is found three times in connection with the desolations to come upon Babylon, Idumea, and Nineveh (Isa. 14:23; 34:11; Zeph. 2:14). This bird belongs to the class of cranes. Its scientific name is Botaurus stellaris. It is a solitary bird, frequenting marshy ground. The Hebrew word (kippod) thus rendered in the Authorized Version is rendered "porcupine" in the Revised Version. But in the passages noted the kippod is associated with birds, with pools of water, and with solitude and desolation. This favours the idea that not the "porcupine" but the "bittern" is really intended by the word.