- The distortion of a wavefront caused by the presence of an obstacle in the sound field.
- Process that produces a diffracted wave. Source: Glossary of Terms in Noise Control Engineering
- A change in the direction of propagation of sound energy in the neighborhood of a boundary discontinuity, such as the edge of a reflective or absorptive surface. Source: http://www.owenscorning.com/around/sound/glossary.asp