semidiameter[-dī am′ət ər]
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
- half a diameter; radius
- Astron. half the angular diameter of a celestial body with a visible disk, as the moon
Used by arrangement with John Wiley & Sons, Inc.
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The apparent radius of a celestial body when viewed as a disk from Earth.