The term MONOTONOUS LOW SOUND can be summarized as a DRONE, which is a five-letter word. A DRONE is a continuous, low humming sound that is often described as monotonous and dull. It is usually created by a sustained note or a repeating rhythm. Drones are commonly used in music, film, and television to create an atmosphere of suspense or tension. They are also used in meditation and relaxation techniques to help people focus and relax.