n. A contrivance for measuring time; a timepiece.n. In the Gr. Ch., an office-book containing the offices for the canonical hours, from matins (mesonycticon) to complin (apodeipnon) inclusive, as well as antiphons, hymns, etc., from the menology and other books, some short occasional offices, and several canons of odes. Generally the calendar is prefixed.n. The science of measuring time, or the principles and art of constructing, regulating, testing, etc., machines for indicating divisions of time, as clocks and watches.