Tromsø (trômsˈöˌ, trŏmsˈöˌ) [key], city (1995 pop. 55,577), capital of Troms co., NW Norway, on the island of Tromsøy; chartered 1794. The chief city of arctic Norway, it has large herring fisheries and is a base for shipping and seal hunting. Manufactures include ships and rope. It is also a starting point for cruise ships. In World War II, the German battleship Tirpitz was sunk (Nov. 12, 1944) by British planes just off Tromsø.