the ratio of signal intensity to noise intensity

S/N (also SNR). The difference in amplitude between a baseband signal and the noise in a portion of the spectrum.

Is the ratio or relationship of accurate electrical signals to unwanted signals like static disturbances creating noise.

the ratio, expressed in dB, between the signal and noise.

(S/N): The system ratio of the integrated energy within the passband envelope to the energy outside this envelope and within the free spectral range.

The amount of useful information to be found in a given ratio Usenet newsgroup. Often used derogatorily, for example: "the signal-to-noise ratio in this newsgroup is pretty low."