sundial

Vertical or horizontal face with divisions that correspond to the hours of the day, which are indicated by the shadow of a gnomon cast by the Sun.

shadow

Dark area that results when the gnomon blocks the sunlight and indicates the time in accordance with the position of the Sun.

gnomon

Part aligned with the Earth’s axis; its shadow indicates the time as it moves over the sundial.

dial

Face marked with numbers over which shadows are cast by the gnomon to indicate the approximate time of day.