Lune

lūn, n. anything in the shape of a half-moon: ( Shak. ) a fit of lunacy.— n. Lunette′ , a little moon: ( fort. ) a detached bastion: a hole in a concave ceiling to admit light: a watch-gla flattened more than usual in the centre: in the R.C. Church, a moon-shaped case of crystal used for receiving the consecrated host. [Fr. lune —L. luna .]