trifocal

[ trahy-foh-kuhl, trahy-foh- ]

adjective

1. Optics. having three foci.
2. (of an eyeglass lens) having three portions, one for near, one for intermediate, and one for far vision.

noun

1. trifocals, eyeglasses with trifocal lenses.

trifocal

adjective

1. having three focuses
2. having three focal lengths

noun

1. plural glasses with trifocal lenses

Word History and Origins

Origin of trifocal¹

First recorded in 1945–50; tri- + focal

Related Words

• glass