(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 dynamical time, TT, ephemeris time, TDT
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
n.; pl.Ephemerides [ L., a diary, Gr. &unr_;, also, a calendar, fr. &unr_;. See Ephemera. ] 1. A diary; a journal. Johnson. [ 1913 Webster ]
2. (Anat.) (a) A publication giving the computed places of the heavenly bodies for each day of the year, with other numerical data, for the use of the astronomer and navigator; an astronomical almanac; as, the “American Ephemeris and Nautical Almanac.” (b) Any tabular statement of the assigned places of a heavenly body, as a planet or comet, on several successive days. [ 1913 Webster ]
3. (Literature) A collective name for reviews, magazines, and all kinds of periodical literature. Brande & C. [ 1913 Webster ]