psychophysics vs just-noticeable difference

psychophysics and just-noticeable difference both are nouns.

Word	Noun	Adjective	Verb	Adverb
psychophysics	Yes	No	No	No
just-noticeable difference	Yes	No	No	No

psychophysics (noun)	just-noticeable difference (noun)
the branch of psychology concerned with quantitative relations between physical stimuli and their psychological effects	(psychophysics) the difference between two stimuli that (under properly controlled experimental conditions) is detected as often as it is undetected