lens
n. countablen. a curved piece of glass or plastic that changes how things look through it. You use it in glasses to see better or in a camera to take photos.
n. a transparent optical device, typically made of glass or plastic, that converges or diverges light rays to form an image. Also refers to the clear structure behind the pupil in the eye that focuses light onto the retina.
I need to clean the lens of my camera before taking pictures.
The optometrist explained that a thicker lens would be necessary to correct my worsening nearsightedness.
By examining the historical event through a sociological lens, the researchers were able to identify patterns of behavior that previous political analyses had overlooked.
Borrowed from Latin lēns (“lentil”), with Medieval Latin later taking on the sense of “lens”, a semantic loan from Arabic عَدْسَة (ʕadsa, “lentil; optic lens”).
Often used metaphorically with 'through a... lens' to describe a specific perspective or way of interpreting information.