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.