1. an instrument that shows the time of day by the shadow cast by a pointer on a marked surface when the sun shines on it

Examples

• The ancient sundial in the garden still accurately shows the time on sunny days.
• Before clocks were invented, people relied on sundials to tell time.
• The shadow on the sundial moved slowly across the numbered face.
• We found an old brass sundial at the antique shop.
• The sundial doesn’t work on cloudy days or at night.
• The park’s sundial was surrounded by beautiful flowers.