I. (ˈ)bī+ adjective
Etymology: International Scientific Vocabulary bi- (I) + focal
1.
a. : having two focal lengths
b. of an eyeglass lens : having one part that corrects for near vision and one for distant vision
2. : marked by two distinct often seemingly incompatible approaches or points of view
the bifocal nature of medieval historiography with its mixture of myth and history — Keith Spalding
an Indian, educated in England and America, and hence able to give a sort of bifocal view of the people and problems of Asia — Nation
II. noun
( -s )
1. : a bifocal glass or lens
2. bifocals plural : eyeglasses with bifocal lenses