Lunette

(loo-net'.) [Fr.: L. luna.] (Opt.) A kind of convex-concave lens, used in the making of spectacles. -(Arch.) An aperture for the admi ion of light in a concave ceiling.-(Fortif.) An enveloped counter guard, or elevation of earth made beyond the second ditch; or, a covered place before the curtain, consisting of two faces that form an angle inwards. [s. 560]