signal-to-noise vs signal-to-noise ratio

signal-to-noise and signal-to-noise ratio both are nouns.

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

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

signal-to-noise and signal-to-noise ratio: the ratio of signal intensity to noise intensity

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

signal-to-noise (noun)	signal-to-noise ratio (noun)
the ratio of signal intensity to noise intensity	the ratio of signal intensity to noise intensity