An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages. An EMU is usually formed of two or more semi-permanently coupled carriages, but electrically powered single-unit railcars are also generally classed as EMUs. The great majority of EMUs are passenger trains, but versions also exist for carrying mail.

A multiple-unit train or simply multiple unit (MU) is a self-propelled train composed of one or more carriages joined, which when coupled to another multiple unit can be controlled by a single driver, with multiple-unit train control.