n. 1 an arched aperture in a domed ceiling to admit light. 2 a crescent-shaped or semicircular space or alcove which contains a painting, statue, etc. 3 a watch-glass of flattened shape. 4 a ring through which a hook is placed to attach a vehicle to the vehicle towing it. 5 a temporary fortification with two faces forming a salient angle, and two flanks. 6 RC Ch. a holder for the consecrated host in a monstrance.
[ F, dimin. of lune (see LUNE) ]