The generic name applied to books in Arabic and Persian that tabulate parameters used for astronomical calculations of positions of the Sun, the Moon, and the five planets of antiquity. Some examples: Zij al-Sindhind, by Khwarizmi (c. 780-850), Az-Zij as-Sabi by al-Battâni (Albatenius) (853-929), Zij-i Ilkhâni by Nassireddin Tusi (1201-1274), Zij-i Sultâni by Ulugh Brg (1437), → Toledan Tables, → Alfonsine Tables.
The word is derived from Mid.Pers. zig, variant zih
"cord, string" (Mod.Pers. zeh "cord, string"); Av. jiiā-
"bow-string," cognate with Skt. jiyā- "bow-string,"
PIE base *gwhi- "thread, tendon" (from which derive
also Gk. bios "bow", L. filum "thread", Russ. žca "thread").