Panama Canal Zone, Canal Zone(noun)

a zone consisting of a strip of land across the Isthmus of Panama that contains the Panama Canal

Panama Canal Zone(ProperNoun)

The territory within Panama, stretching along the course of the Panama Canal but excluding the sea port cities Panama City and Colon, which was exclusively administered by the U.S.A. (which appointed governors) under the 18 November 1903 lease treaty, even before the canal opened (in 1914), until the return of state control on 30 September 1979, after which only the canal itself remained under the US-controlled Panama Canal Commission till 1999.