Acoustics is a branch of physics that studies sound, namely mechanical waves in gases, liquids, and solids. A scientist that works in the field of acoustics is an acoustician. The application of acoustics in technology is called acoustical engineering. There is often much overlap and interaction between the interests of acousticians and acoustical engineers.
...*coustics is characterized by its reliance on combinations of physical principles drawn from other sources; and that the primary task of modern physical acoustics is to effect a fusion of the principles normally adhering to other sciences into a coherent basis for understanding, measuring, controlling, and using the whole gamut of vibrational phenomena in any material.
Origins in Acoustics. F.V. Hunt. Yale University Press, 1978