Meaning of trifocal

tri•fo•cal

Pronunciation: (trī-fō'kul, trī'fō"-), [key]
— adj.
  1. having three foci.
  2. (of an eyeglass lens) having three portions, one for near, one for intermediate, and one for far vision.
—n.
  1. eyeglasses with trifocal lenses.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.