Earth & SkyGreek → English
Ephemeris
/ɪˈfɛmərɪs/noun
A table giving the calculated positions of celestial bodies at regular intervals.
The Greek roots
ἐπί
epí
upon, for
ἡμέρα
hēméra
day
Literally: “for the day, a daybook”
The story of the word
An ἐφημερίς was a daybook, a record of what happened on the day. Alexander's court kept them, and later historians quarried those journals for the story of his final illness. Astronomy took the word for a table of where each body will be, day by day, and navigators steered by it for four centuries. Ephemeral is the same word in adjective form: lasting one day.
- How it travelled
- Ancient Greek → Latin → English
- First recorded
- 16th century
Same family
ephemeralephemera
In a sentence
The observatory checked the ephemeris before pointing the dish.