focal-plane

focal plane

noun Optics.
1.
a plane through a focal point and normal to the axis of a lens, mirror, or other optical system. Compare principal plane.
2.
the transverse plane in a telescope where the real image of a distant view is in focus.

Origin:
1890–95

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To focal-plane
Collins
World English Dictionary
focal plane
 
n
1.  the plane that is perpendicular to the axis of a lens or mirror and passes through the focal point
2.  the plane in a telescope, camera, or other optical instrument in which a real image is in focus

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature