"vertical shaft that tells time by the shadow it casts" (especially the triangular plate on a sundial), 1540s, from Latin gnomon, from Greek gnomon "indicator (of a sundial), carpenter's rule," also, in plural, "the teeth that mark the age of a horse or mule," literally "one that discerns or examines," from gignoskein "to come to know" (see gnostic (adj.)). In geometry from 1560s, from a use in Greek. In early use in English sometimes folk-etymologized as knowman. Related: Gnomonic.
实用例句
1. In all cases the gnomon lies in the plane of the meridian.
表始终都处于子午面内.
来自辞典例句
2. The gnomon - and - ruler indicates the time by the length of the shadow of stylus in the sun.
