noun
- half the diameter of a circle or sphere; the radius
Usage: technical; geometry
Examples
- The semidiameter of the circle measures 5 centimeters.
- To find the area, we need the semidiameter of the sphere.
- The astronomer calculated the semidiameter of the planet.
- Draw a line from the center to the edge equal to the semidiameter.
- The semidiameter is exactly half the distance across the circle.