An Etymological Dictionary of Astronomy and Astrophysics

A transparent optical component consisting of one or more pieces of optical glass with surfaces so curved (usually spherical) that they serve to converge or diverge the transmitted rays from an object, thus forming a real or virtual image of that object.

Etymology (EN): From L. lens (gen. lentis) “lentil,” cognate with Gk. lathyros, on analogy of the double-convex shape.

Etymology (PE): Adasi, related to adas “lentil,” from Ar. ‘adas.
The original Pers. terms for lentil are: mažu, mažâné, (Gilaki, Tabari) marju, marji, murje, marjum, (Laki) noži, (Aftari) marju, Mid.Pers. mijûg “lentil;” cf. Skt. masura- “lentil.”