Acoustics is the science of sound and its properties. It involves the study of how sound waves travel and interact with objects in their environment. The term 'acoustics' can also refer to the application of this science, such as in the design of sound-proof rooms or the use of acoustic instruments. The crossword solutions BEL (3 letters) and DAMP (4 letters) are both related to acoustics. BEL is an abbreviation for the unit of sound intensity, bels, which is used to measure the loudness of a sound. DAMP is an acronym for damping, which is the process of reducing the amplitude of a sound wave by absorbing its energy.