The crossword solution for the term 'PLAY MONOTONOUSLY' is DRONE. A DRONE is a sound that is sustained and continuous, without any variation in pitch or volume. It is often used to describe a monotonous sound, such as a hum or buzz. In music, a DRONE is a sustained note or chord that provides a harmonic foundation for a melody or other musical elements. It is commonly used in folk music, classical music, and some forms of jazz.