A keyboard instrument is a musical instrument played using a keyboard. The most common of these is the piano. Some other types of keyboard instruments include celestas, which are struck idiophones operated by a keyboard, carillons, which are highly different instruments that are usually housed in bell towers or belfries of churches or other municipal buildings, and other non-acoustic instruments, such as various electronic organs, synthesizers, and keyboards designed to imitate the sound of other musical sounds.
Today, the term "keyboard" is mostly commonly used to refer to keyboard-style synthesizers. Under the fingers of a sensitive performer, the keyboard may also be used to control dynamics, phrasing, shading, articulation, and other elements of expression, depending on the design and inherent capabilities of the instrument.