A rock band or pop band is a small musical ensemble that performs rock music, pop music, or a related genre. A four-piece band is the most common configuration in rock and pop music. In the early years, the configuration was typically two guitarists (a lead guitarist and a rhythmguitarist, with one of them singing lead vocals), a bassist, and a drummer (e.g. the Beatles and KISS). Another common formation is a vocalist who does not play an instrument, electric guitarist, bass guitarist, and a drummer (e.g. the Who, the Monkees, Led Zeppelin and U2). Instrumentally, these bands can be considered as trios. Sometimes, in addition to electric guitars, electric bass, and drums, also a keyboardist (especially a pianist) plays.
Additionally, rock and pop bands can also include boy bands or girl bands, which many times have bands where the members do not play any instruments but sing and dance instead. Such is the case of Menudo, the Spice Girls and K-pop bands, for example.
