W6 may refer to: W6 (tram), a class of electric trams built by the Melbourne & Metropolitan Tramways Board. a particular width for a structural steel I-beam a postcode district in the W postcode area Wizz Air (IATA code W6) 7th step of the W0-W6 scale for the classification of meteorites by weathering W6 (loading gauge) on the British rail network Weltmeister W6, a Chinese car