response time vs reaction time

response time and reaction time both are nouns.

Word	Noun	Adjective	Verb	Adverb
response time	Yes	No	No	No
reaction time	Yes	No	No	No

As nouns, response time and reaction time are synonyms defined as:

response time and reaction time: the time that elapses between a stimulus and the response to it

Other synonyms of response time include latency, latent period.

response time (noun)	reaction time (noun)
the time that elapses between a stimulus and the response to it	the time that elapses between a stimulus and the response to it