The masu salmon, also known as masu or cherry trout in Japan, is a species of salmonid belonging to the genus Oncorhynchus, found in the North Pacific along Northeast/East Asian coasts from the Russian Far East to south through Korea, Japan and Taiwan. Although generally accepted as a salmon in the West, the fish is actually regarded as a trout in Japan as it is the most commonly seen freshwater salmonid in the Japanese archipelago.

Oncorhynchus is a genus of ray-finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributaries of the North Pacific basin. The genus contains twelve extant species, namely six species of Pacific salmon and six species of Pacific trout, all of which are migratory mid-level predatory fish that display natal homing and semelparity.