terrestrial time vs TDT

terrestrial time and TDT both are nouns.

Word	Noun	Adjective	Verb	Adverb
terrestrial time	Yes	No	No	No
TDT	Yes	No	No	No

As nouns, terrestrial time and TDT are synonyms defined as:

terrestrial time and TDT: (astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions

Other synonyms of terrestrial time include ephemeris time, terrestrial dynamical time, TT.

terrestrial time (noun)	TDT (noun)
(astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions	(astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions