W1 could refer to: * W1, a postcode district in the W postcode area of London * British NVC community W1 (Salix cinerea - Galium palustre woodland), one of the woodland communities of the British National Vegetation Classification * W-1 tool steel, a water-hardening steel * one of four manuscripts containing the Magnus Liber, or Magnus liber organi, a compilation of medieval music. The term is derived from the Wolfenbüttel library which holds the manuscript (Herzog August Bibliothek). * GN W-1, an electric locomotive built for the Great Northern Railway * LNER Class W1, an experimental locomotive designed by Sir Nigel Gresley for the London and North Eastern Railway * second step of the W0-W6 scale for the classification of meteorites by weathering * Wrestle-1, a Japanese professional wrestling promotion * The computational complexity class W /nowiki> in parameterized complexity * The Apple W1 wireless pairing chip primarily used in AirPods * W1 tram, a class of electric trams built by the Melbourne & Metropolitan Tramways Board. W-1 could refer to: * U.S. uniformed services pay grades#Warrant Officer pay grades

See also