In this meaning, multifocal describes contact lenses or glasses that help you see things that are near and things that are far. One pair is trying to do jobs that old single-focus lenses would not do in one go.

The older, famous kind is bifocal: two zones, often with a line — distance on top, reading at the bottom. Multifocal usually means more than two focuses, or a smooth change from far to near (what shops often call progressive lenses). People in clinics and glasses shops use these words a little loosely. A patient may say “multifocal” for any glasses that do both near and far. A careful eye doctor will split bifocal, trifocal, and progressive / multifocal. For a learner, the core idea is enough: one pair, more than one distance.

You will also meet multifocal in medicine, where it means a problem that shows up in several spots. That is a different use. Here we are in the eye shop.