Dictionary.com
definitions
  • synonyms

bifocal

[bahy-foh-kuh l, bahy-foh-]
See more synonyms for bifocal on Thesaurus.com
adjective
  1. Chiefly Optics. having two foci.
  2. (of an eyeglass or contact lens) having two portions, one for near and one for far vision.
Show More
noun
  1. bifocals, bifocal eyeglasses or contact lenses.
Show More

Origin of bifocal

An Americanism dating back to 1885–90; bi-1 + focal
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for bifocal

Historical Examples

  • His most direct contribution to medicine was the invention for his own use of bifocal eyeglasses.

    Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 1 "Franciscans" to "French Language"

    Various

  • Any other fish or mammal would have been just as likely as Anableps to begin the development of a bifocal eye.

    Parallel Paths

    Thomas William Rolleston


British Dictionary definitions for bifocal

bifocal

adjective
  1. optics having two different focuses
  2. relating to a compound lens permitting near and distant vision
Show More
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

Word Origin and History for bifocal

adj.

"having two foci," 1844, from bi- + focal.

Show More
Online Etymology Dictionary, © 2010 Douglas Harper

bifocal in Medicine

bifocal

(bī-fōkəl, bīfō′-)
adj.
  1. Having two focal lengths.
  2. Having one section that corrects for distant vision and another that corrects for near vision.
Show More
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.