D4 or D-4 may mean: · D4 video connector, a type of analog video connector found on Japanese consumer electronics · D4 , a programming language of the Dataphor system · D4 framing standard, a framing standard for traditional time-division multiplexing · The D4, a rock band from Auckland, New Zealand · Dublin 4, a Dublin postcode · Parallel Lines, the fourth videogame in the Driver series · Motorway D4 , a motorway in southwestern Slovakia D4 may also be: · d4, a 4-sided die · A square on a chessboard, as well as a move or even chess opening pertaining to that square · The Alidaunia IATA code · A model of tractor made by Caterpillar, Inc. D4D4D4