The term cornice comes from Italian cornice, meaning "ledge."
Cornice molding is generally any horizontal decorative molding which crowns any building or furniture element: the cornice over a door or window, for instance, or the cornice around the edge of a pedestal. A simple cornice may be formed just with a crown molding.
The function of the projecting cornice is to throw rainwater free of the building's walls. In residential building practice, this function is handled by projecting gable ends, roof eaves, and gutters. The elimination of the cornice has been important enough in modernist architecture, often simply for demands of style, that elaborate internal drainage systems are provided.