From HomoExcelsior

1. The quality or condition of being sensitive. 2. The capacity of an organ or organism to respond to stimulation. 3. The degree of response of a receiver or an instrument to an incoming signal or to a change in the incoming signal; the signal strength required by an FM tuner to reduce noise and distortion. 4. The degree of response of a plate or film to light, especially to light of a specified wavelength.

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