
of an electroacoustic transducer for sound reception, for a specified frequency, quotient of the output open-circuit voltage by the sound pressure acting on the part of the transducer designed to receive sound NOTE - If the load impedance is other than that of an open circuit, it shall be specified.
Found on
http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=801-25-53

The feature in a synthesizer or Keyboard Controller of After Touch (a control or operational function of a synthesizer where pressing a key after it has been pressed, and before it is released, will activate a control command that can be set by the player).
Found on
http://www.encyclo.co.uk/local/20447

See aftertouch, channel pressure, poly pressure.
Found on
http://www.encyclo.co.uk/local/22285
No exact match found.