universal time vs UTC

universal time and UTC both are nouns.

Word	Noun	Adjective	Verb	Adverb
universal time	Yes	No	No	No
UTC	Yes	No	No	No

As nouns, UTC is a hyponym of universal time; that is, UTC is a word with a more specific, narrower meaning than universal time:

universal time: the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere
UTC: Greenwich Mean Time updated with leap seconds

Other hyponyms of universal time include coordinated universal time.

universal time (noun)	UTC (noun)
the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere	Greenwich Mean Time updated with leap seconds