The Collaborative International Dictionary
diaphonics
Diacoustics \Di`a*cous"tics\, n. [Cf. F. diacoustique.] 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.
Wiktionary
diaphonics
n. The doctrine of refracted sound; diacoustics.