S/N vs signal-to-noise ratio

S/N and signal-to-noise ratio both are nouns.

Word	Noun	Adjective	Verb	Adverb
S/N	Yes	No	No	No
signal-to-noise ratio	Yes	No	No	No

As nouns, S/N and signal-to-noise ratio are synonyms defined as:

S/N and signal-to-noise ratio: the ratio of signal intensity to noise intensity

Other synonyms of S/N include signal/noise, signal/noise ratio, signal-to-noise.

S/N (noun)	signal-to-noise ratio (noun)
the ratio of signal intensity to noise intensity	the ratio of signal intensity to noise intensity