trifocal

US: /traɪˈfoʊkəl, ˈtraɪˌfoʊ-/ ,(trī fō′kəl, trī′fō′-)

WordReference Random House Learner's Dictionary of American English © 2025

tri•fo•cal /traɪˈfoʊkəl, ˈtraɪˌfoʊ-/   adj. 

1. Optics (of a lens) having three areas that focus light rays.
2. (of an eyeglass lens) having three portions, one for near, one for middle, and one for far vision.

n. 

3. trifocals, [plural] eyeglasses with trifocal lenses.

WordReference Random House Unabridged Dictionary of American English © 2025

tri•fo•cal  (trī fō′kəl, trī′fō′-), 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.

• tri- + focal 1945–50

Collins Concise English Dictionary © HarperCollins Publishers::

trifocal adjective / traɪˈfəʊk^əl/

1. having three focuses
2. having three focal lengths

noun / traɪˈfəʊk^əl ˈtraɪˌfəʊk^əl/

1. (plural) glasses with trifocal lenses