- a city in and the capital of Basel-Stadt, in NW Switzerland, on the Rhine River.
- a canton in N Switzerland, divided into two independent areas.
- a demicanton in N Switzerland: virtually coextensive with the city of Basel. 14 sq. mi. (36 sq. km). Capital: Basel.
- a variant spelling of Basle
city in northwestern Switzerland, founded 44 C.E. as Robur (from Latin roburetum “oak grove”); renamed 374 as Basilia (from Greek basilea “royal”) when it became the “royal” fortress of Valentinian I.