Sundial

n.

1.

An instrument to show the time of day by means of the shadow of a gnomon, or style, on a plate. Sundial shell (Zool.) any shell of the genus Solarium. See Solarium.

Noun

1.

sundial - timepiece that indicates the daylight hours by the shadow that the gnomon casts on a calibrated dial

gnomon, timekeeper, timepiece