(a.) "hour", hence "clock".

1. In technology.

Monumental water-clocks are described in detail in two Arabic treatises. Al-Ḏj̲azarī [q.v. in Suppl.] in his book on mechanical contrivances completed in Diyār Bakr in 602/1206 describes two such machines. Riḍwān b. al-Sāʿātī, in a treatise dated 600/1203, describes the water-clock built by his father Muḥammad at the Ḏj̲ayrūn gate in Damascus (see E. Wiedemann and F. Hauser, Über die Uhren in Bereich der Islamischen Kultur , in Nova Acta der Kaiserl . Leop . Deutschen Akad . der Naturforscher , ciii [1918], 167-272). It fell into disr…