Humpback Hump"back`, n. [Cf. {Hunchback}.] 1. A crooked back; a humped back. --Tatler. [1913 Webster]

2. A humpbacked person; a hunchback. [1913 Webster]

3. (Zo["o]l.) (a) Any whale of the genus {Megaptera}, characterized by a hump or bunch on the back. Several species are known. The most common ones in the North Atlantic are {Megaptera longimana} of Europe, and {Megaptera osphyia} of America; that of the California coasts is {Megaptera versabilis}. (b) A small salmon ({Oncorhynchus gorbuscha}), of the northwest coast of America; the {humpbacked salmon}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.