Definition of trifocal in English:
 trifocal
adjective trʌɪˈfəʊk(ə)lˈtraɪˌfoʊk(ə)l
(of a pair of glasses) having lenses with three parts with different focal lengths.
 Example sentencesExamples
-  A bifocal lens corrects both far and near vision, while a trifocal also has an intermediate zone.
 -  And trifocal contact lenses are placed a little bit higher in such a way that the area for intermediate zone is on the pupil of the eye.
 -  Additionally, where bifocal or trifocal lenses are not desirable, disposable lens shields and ‘press-on’ lenses in the upper and/or upper-central regions of the lens have been proposed.
 -  One analysis reports that neck pain experienced by middle-aged patients often coincides with their first prescription for bifocal or trifocal glasses.
 
noun trʌɪˈfəʊk(ə)lˈtraɪˌfoʊk(ə)l
trifocalsA pair of glasses with trifocal lenses.
 Example sentencesExamples
-  In addition to this, those glasses were extra-strength double-duty army trifocals or something.
 -  I paid $100 American for blended trifocals, and they are the best glasses I have ever owned.
 -  And if you wear bifocals or trifocals, keep in mind that you may have a tendency to tilt your head backwards so that you can see through the lower portion of your glasses.
 -  Older aviators and farsighted aviators may require trifocals, which have two sets of near - vision refractive glass to focus on intermediate and near distances.
 -  Scopes also help mature shooters continue in the sport longer, he said, because finding iron sights through bifocals and trifocals can be challenging.
 
  Definition of trifocal in US English:
 trifocal
adjectiveˈtrīˌfōk(ə)lˈtraɪˌfoʊk(ə)l
(of a pair of glasses) having lenses with three parts with different focal lengths.
 Example sentencesExamples
-  And trifocal contact lenses are placed a little bit higher in such a way that the area for intermediate zone is on the pupil of the eye.
 -  Additionally, where bifocal or trifocal lenses are not desirable, disposable lens shields and ‘press-on’ lenses in the upper and/or upper-central regions of the lens have been proposed.
 -  One analysis reports that neck pain experienced by middle-aged patients often coincides with their first prescription for bifocal or trifocal glasses.
 -  A bifocal lens corrects both far and near vision, while a trifocal also has an intermediate zone.
 
nounˈtrīˌfōk(ə)lˈtraɪˌfoʊk(ə)l
trifocalsA pair of glasses with trifocal lenses.
 Example sentencesExamples
-  Scopes also help mature shooters continue in the sport longer, he said, because finding iron sights through bifocals and trifocals can be challenging.
 -  I paid $100 American for blended trifocals, and they are the best glasses I have ever owned.
 -  And if you wear bifocals or trifocals, keep in mind that you may have a tendency to tilt your head backwards so that you can see through the lower portion of your glasses.
 -  Older aviators and farsighted aviators may require trifocals, which have two sets of near - vision refractive glass to focus on intermediate and near distances.
 -  In addition to this, those glasses were extra-strength double-duty army trifocals or something.