A plane, or curved, narrow surface, either sunk or
   projecting, used for decoration by means of the lights and shades upon
   its surface. Moldings vary greatly in pattern, and are generally used
   in groups, the different members of each group projecting or
   retreating, one beyond another. See Cable, n., 3, and Crenelated
   molding, under Crenelate, v. t.