means A curved piece of glass or other transparent material that bends light to focus it, used in eyes, cameras, glasses, telescopes, and microscopes.

from From Latin 'lens,' meaning 'lentil' — the little legume. Early double-convex glasses had that same plump, rounded shape, bulging in the middle and tapering at the edges, so opticians simply named them after the bean they resembled. Every time you say 'lens,' you're quietly comparing it to soup.