Definition

The distance from the center to the edge of a circular or spherical object, often used in astronomy to describe celestial bodies.

Example

The semidiameter of the moon is about 1,737 kilometers.

Conversation

Have you ever looked at the moon through a telescope?

Yeah, it's fascinating how you can see details on its surface.

I read that the moon's semidiameter is about 1,737 kilometers.

That's really interesting! It makes you appreciate how close it is to us.

Synonyms & Antonyms

Root Explanation

Semidiameter → It is formed from "semi-" (meaning half) and "diameter" (from Greek "diametros", meaning measure across). The word "semidiameter" refers to half of the diameter, or the distance from the center of a circle to its edge.

Memory Tip

Think of 'semi-' meaning half, and 'diameter' as the measure across a circle. This helps you remember that a semidiameter is half the distance across a circle.

Visually Confused Words