Sundial

Origin

sun + dial

Full definition of sundial

Noun

1. A simple timekeeping device in which the shadow cast by a vertical pole or plate (the gnomon) is used to indicate the time of day.
• 1907, Robert Chambers, The Younger Set Chapter 8, “I never understood it,” she observed, lightly scornful. “What occult meaning has a sun-dial for a spooney ? I’m sure I don't want to read riddles into a strange gentleman’s optics.”