1. the part of a sundial that casts a shadow to indicate the time of day
2. in geometry, a parallelogram formed when a smaller parallelogram is removed from a larger one
Usage: mathematics

Examples

• The gnomon on the ancient sundial was carefully angled to align with Earth's axis.
• As the sun moved across the sky, the gnomon's shadow traced the hours on the dial.
• The garden featured a marble sundial with an ornate bronze gnomon.
• In the geometry proof, the student calculated the area of the gnomon by subtracting the smaller parallelogram from the larger one.
• The gnomon's length and angle determine the accuracy of a sundial's time measurement.