Definitions

1. adjective

having three foci or focal points

“The trifocal lens in her glasses corrected her nearsightedness, farsightedness, and astigmatism.”

2. noun

a lens or system with three foci or focal points

“The trifocal lens used in her reading glasses greatly improved her vision.”

3. adverb

in a way that involves or affects three focal points

“The new trifocal approach to therapy focused on the patient’s emotional, psychological, and physical well-being.”