24/7 vs uptime

24/7 and uptime both are nouns.

Word	Noun	Adjective	Verb	Adverb
24/7	Yes	No	No	No
uptime	Yes	No	No	No

As nouns, uptime is a hypernym of 24/7; that is, uptime is a word with a broader meaning than 24/7:

24/7: uptime is 24 hours a day 7 days a week
uptime: a period of time when something (as a machine or factory) is functioning and available for use

24/7 (noun)	uptime (noun)
uptime is 24 hours a day 7 days a week	a period of time when something (as a machine or factory) is functioning and available for use