bifocal

adjective

1. Chiefly Optics. having two foci.
2. (of an eyeglass or contact lens) having two portions, one for near and one for far vision.

noun

3. bifocals, bifocal eyeglasses or contact lenses.

adjective

1. optics having two different focuses
2. relating to a compound lens permitting near and distant vision

adj.

“having two foci,” 1844, from bi- + focal.

adj.

1. Having two focal lengths.
2. Having one section that corrects for distant vision and another that corrects for near vision.