/truy foh"keuhl, truy"foh'-/ , adj.
1. Optics. having three foci.
2. (of an eyeglass lens) having three portions, one for near, one for intermediate, and one for far vision.
n.
3. trifocals , eyeglasses with trifocal lenses.
[ 1945-50; TRI- + FOCAL ]