Definition of semidiameter in English:

Share this entry


Pronunciation: /ˌsemēdīˈamitər/ /ˌsemˌī-/


Astronomy & Geometry
Half of a diameter; radius.
Example sentences
  • The moon will, at the full, be totally eclipsed, if its latitude is less than the difference between its own semidiameter, and that of the earth's shadow.
  • By the semidiameter of a celestial object, is meant the angle which the radius of its apparent circular disc subtends at the eye of the observer.


Late Middle English: from late Latin.

For editors and proofreaders

Syllabification: sem·i·di·am·e·ter

Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.