Question

what do you mean by sundial?

Answer 1

An instrument showing the time by the shadow of a pointer cast by the sun on to a plate marked with the hours of the day.

Answer 2

Explanation:

Sundial, the earliest type of timekeeping device, which indicates the time of day by the position of the shadow of some object exposed to the sun's rays. ... As the day progresses, the sun moves across the sky, causing the shadow of the object to move and indicating the passage of time.