Keyboard instruments refer to musical instruments that are played using a keyboard. Some common synonyms for keyboard instruments include "piano," "organ," "harpsichord," "synthesizer," and "clavichord." The piano is perhaps one of the most well-known keyboard instruments, featuring a set of keys that trigger hammers to strike strings. The organ, on the other hand, uses pipes to produce sound and is often associated with church music. The harpsichord is a keyboard instrument that is similar to the piano but uses a different mechanism to produce sound. Synthesizers are electronic keyboard instruments that create a variety of sounds through the use of oscillators and filters. Finally, the clavichord is a keyboard instrument that produces sound by directly striking strings with hammers.