sundial

noun

Etymology: From sun + dial, a clarification of dial after it was used for other objects as well.

1. A device measuring the time of day by the position of a shadow cast by a pole or plate (gnomon) upon an engraved series of marks.

   “The birdbath includes a small gnomon that acts as a sundial with markings on the basin if it's aligned correctly with the sun.”

   “Elbows almost touching they leaned at ease, idly reading the almost obliterated lines engraved there. "I never understood it," she observed, lightly scornful. "What occult meaning has a sun-dial for the spooney? I'm sure I don't want to read riddles in a strange gentleman's optics."”

2. A sea snail of the genus Heliacus.