A carillon ( KARR-ə-lon, kə-RIL-yən) is a pitched percussion instrument that is played with a keyboard and consists of at least 23 bells. The bells are cast in bronze, hung in fixed suspension, and tuned in chromatic order so that they can be sounded harmoniously together. They are struck with clappers connected to a keyboard of wooden batons played with the hands and pedals played with the feet. Often housed in bell towers, carillons are usually owned by churches, universities, or municipalities. They can include an automatic system through which the time is announced and simple tunes are played throughout the day.

A bell tower is a tower that contains one or more bells, or that is designed to hold bells even if it has none. Such a tower commonly serves as part of a Christian church, and will contain church bells, but there are also many secular bell towers, often part of a municipal building, an educational establishment, or a tower built specifically to house a carillon. Church bell towers often incorporate clocks, and secular towers usually do, as a public service.