UT1 vs Greenwich Mean Time

UT1 and Greenwich Mean Time both are nouns.

Word	Noun	Adjective	Verb	Adverb
UT1	Yes	No	No	No
Greenwich Mean Time	Yes	No	No	No

As nouns, UT1 and Greenwich Mean Time are synonyms defined as:

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

Other synonyms of UT1 include GMT, Greenwich Time, universal time, UT.

UT1 (noun)	Greenwich Mean 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