Reciprocity

Acoustics

If in a space filled with air which is partly bounded by finitely extended fixed bodies and is partly unbounded, sound waves being excited at any point A, the resulting velocity-potential at a second point B is the same both in magnitude and phase, as it would have been at A, had B been the source of the sound.

Electronics

The property of interchangeability of the same antenna for transmitting and receiving.

See also: Antenna, Sound.