In music and music theory, the beat is the basic unit of time, the pulse (regularly repeating event), of the mensural level (or beat level). The beat is often defined as the rhythm listeners would tap their toes to when listening to a piece of music, or the numbers a musician counts while performing, though in practice this may be technically incorrect (often the first multiple level). In popular use, beat can refer to a variety of related concepts including: tempo, meter, specific rhythms, and groove.

Beat music, British beat, or Merseybeat (after bands from Liverpool and nearby areas beside the River Mersey) is a pop and rock music genre that developed in the United Kingdom in the early 1960s. Beat music is a fusion of rock and roll (mainly Chuck Berry guitar style and the midtempo beat of artists like Buddy Holly), doo-wop, skiffle and R&B. The genre provided many of the bands responsible for the British Invasion of the American pop charts starting in 1964, and provided the model for many important developments in pop and rock music, including the format of the rock group around lead, rhythm and bass guitars with drums.