ephemeris noun. [ɪ'fɛm(ǝ)rɪs, -'fi:m-] Also (from the pl.) ephemerides. Pl. ephemerides [ɛfɪ'mɛrɪdi:z] E16.
[Latin from Greek, from ephēmeros: see EPHEMERA noun¹.]
1. A table giving the position of a celestial object at daily or other regular intervals throughout a period; a book containing such tables and other astronomical information, an astronomical almanac. E16.

2. gen. An almanac, a calendar. Now rare or obsolete. L16.

3. A diary, a journal. L16-L17.

4. = EPHEMERA noun¹ 2, 3. E19.

Comb.:
ephemeris time Astronomy a time-scale defined in terms of the orbital motion of the planets.

■ ephemerist noun¹ a person who makes or uses an ephemeris M17-M18.

[TahlilGaran] English Dictionary ▲