"Fretless" refers to musical instruments, particularly string instruments, that do not have frets, which are the raised strips on the fingerboard that help players find specific notes. This design allows for a smoother, continuous pitch, enabling musicians to create unique sounds and expressiveness. Common fretless instruments include the fretless bass, violin, and cello. Fretless instruments require precise finger placement, as there are no frets to guide the player. This can enhance the player's ability to perform techniques like slides and vibrato, making the sound more fluid. Many genres, including jazz and world music, often feature fretless instruments for their distinctive tonal qualities.