Acoustics :: Acoustics (n.) The science of sounds, teaching their nature, phenomena, and laws..
Catacoustic :: Catacoustic (n.) That part of acoustics which treats of reflected sounds or echoes See Acoustics.
Diacoustic :: Diacoustic (a.) Pertaining to the science or doctrine of refracted sounds.
Diacoustics :: Diacoustics (n.) That branch of natural philosophy which treats of the properties of sound as affected by passing through different mediums; -- called also diaphonics. See the Note under Acoustics.