An Etymological Dictionary of Astronomy and Astrophysics

A table of computed positions occupied by a celestial body over successive intervals of time such as daily; plural ephemerides.

Etymology (EN): From L. ephemeris “day book, diary,” from Gk. ephemeris “diary, account book,” from ephemeros “short-lived, lasting but a day,” from → epi “on, upon”

• hemerai, dative of hemera “day.”

Etymology (PE): Ruzij, from ruz, → day + zij “astronomical table,” from Mid.Pers. zig “astronomical table,” originally “string,” since the lines of a table were compared to strings used on a weaver’s instrument, variant zih, meaning “cord, string” (Modern Persian zeh “cord, string”); Av. jiiā- “bow-string;” cf. Skt. jiyā- “bow-string;” PIE base *g^whi- “thread, tendon” (from which derive also Gk. bios “bow;” L. filum “thread;” Russ. žca “thread”).