- Also called principal focus. Optics. either of two points on the axis of a mirror, lens, or other optical system, one point being such that rays diverging from it are deviated parallel to the axis upon refraction or reflection by the system and the other point being such that rays parallel to the axis of the system converge to the point upon refraction or reflection by the system.
- the point at which all elements or aspects converge; center of activity or attention: The focal point of our discussion was the need for action.
- the central or principal point of focus.
Origin of focal point
First recorded in 1705–15
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for focal point
We are at the focal-point of the present battle in Foureaux Wood (near Guillemont).Now It Can Be Told
- Also called: principal focus, focus the point on the axis of a lens or mirror to which parallel rays of light converge or from which they appear to diverge after refraction or reflection
- a central point of attention or interest
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- The point at which all radiation coming from a single direction and passing through a lens or striking a mirror converges. Also called focus
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.