TDT

Từ điển WordNet v3.1 - WordNet Dictionary

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
• Syn:
terrestrial time, TT, terrestrial dynamical time, ephemeris time
• Topics:
astronomy, uranology
• Hypernyms:
time unit, unit of time