Other forms: lenses
A lens is the curved glass that bends light in glasses, cameras, and eyes. A camera lens, contact lens, the lens of the eye.
The curve does everything: light slows entering the glass and bends, and the shape decides where it meets. The eye's lens changes shape to focus and stiffens with age, which is why reading glasses arrive in middle life. The word is Latin for a lentil, after the shape.
1nounlensA curved piece of glass that bends light.
“He cleaned the camera lens with a soft cloth before taking the picture.”
lens is an optical part.
Latin lens means a lentil. The optical sense comes from the shape of a double-convex lens.
Arabic
عَدَسَة — lentil; optic lens
Latin
lēns — lentil
Medieval Latin
lēns
English, today
lens
Borrowed from Medieval Latin lēns, from lēns. Borrowed from Latin lēns (“lentil”), with Medieval Latin later taking on the sense of “lens”, a Arabic عَدَسَة (“lentil; optic lens”); the similar shape is the common factor.
Etymology from Wiktionary, CC BY-SA