UT1 vs universal time

UT1 and universal time both are nouns.

Word	Noun	Adjective	Verb	Adverb
UT1	Yes	No	No	No
universal time	Yes	No	No	No

As nouns, UT1 and universal time are synonyms defined as:

UT1 and universal time: the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere

Other synonyms of UT1 include GMT, Greenwich Mean Time, Greenwich Time, UT.

UT1 (noun)	universal time (noun)
the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere	the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere