Meaning

noun a transparent optical device used to converge or diverge transmitted light and to form images

noun genus of small erect or climbing herbs with pinnate leaves and small inconspicuous white flowers and small flattened pods: lentils

noun (metaphor) a channel through which something can be seen or understood

originEtymology tree Latin lēns Arabic عَدْسَة (ʕadsa)sl. Medieval Latin lēnsbor. English lens 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”); the similar shape is the common factor.

Etymology from Wiktionary, CC BY-SA 3.0