History
History
Synonyms
UK
US
Meaning:
bifocal

(especially of lenses in spectacles) design for both distant and near vision

glass for vision

lens

a piece of glass (or substance like glass) with one or both sides curved, used in spectacles, cameras, telescopes, microscopes and other optical instruments

glass for vision

TRIFOCAL as in Wiktionary
TRIFOCAL as in Wikipedia