Noah Webster's Dictionary (n.) An instrument to show the time of day by means of the shadow of a gnomon, or style, on a plate.

Multi-Version Concordance Sundial (1 Occurrence) Isaiah 38:8 Behold, I will cause the shadow on the sundial, which has gone down on the sundial of Ahaz with the sun, to return backward ten steps. So the sun returned ten steps on the sundial on which it had gone down."'" (WEB)