TDT

1 definition found

From WordNet (r) 2.0 [wn]:

  TDT
       n : (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}]