Bifocals
Origin
From bi- + focal (see focus), coined in 1824 by John Isaac Hawkins, inventor of trifocals. When the concept of bifocals was originally conceived by Benjamin Franklin, he called them double spectacles.
Full definition of bifocals
Noun
bifocals
(plural only)- spectacles that have corrective lenses of two different powers; used by people who need both distance and reading glasses