sunglass

A convex lens used to focus the sun’s rays and produce heat, especially for ignition.

Eyeglasses with tinted or polarizing lenses to protect the eyes from the sun’s glare.

A burning-glass.

Same as shade-glass; a screen of colored glass attached to a sextant to diminish the apparent brightness of the sun.

A convex lens of glass for producing heat by converging the sun’s rays into a focus.

Singular form of sunglasses; used chiefly in compounds

a convex lens that focuses the rays of the sun; used to start a fire