- The use of noise of any kind to interfere with the audibility of another sound. For any given intensity, low-pitched tones have a greater masking effect than those of a high pitch.
- In audiology, the use of a noise applied to one ear while testing the hearing of the other ear.
- The hiding of smaller rhythms in the brain wave record by larger and slower ones, the waveform of which they distort.
- In dentistry, an opaque covering used to camouflage the metal parts of a prosthesis.
- In radiography, superimposition of an altered positive image on the original negative to produce an enhanced copy photographically.