universal time vs GMT

universal time and GMT both are nouns.

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

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

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

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

universal time (noun)	GMT (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