trifocal

[trahy-foh-kuh l, trahy-foh-]
See more synonyms for trifocal on Thesaurus.com
adjective
  1. Optics. having three foci.
  2. (of an eyeglass lens) having three portions, one for near, one for intermediate, and one for far vision.
noun
  1. trifocals, eyeglasses with trifocal lenses.

Origin of trifocal

First recorded in 1945–50; tri- + focal
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018


British Dictionary definitions for trifocal

trifocal

adjective (traɪˈfəʊkəl)
  1. having three focuses
  2. having three focal lengths
noun (traɪˈfəʊkəl, ˈtraɪˌfəʊkəl)
  1. (plural) glasses with trifocal lenses
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