The term 'cut into metal' can be accomplished by two different processes: engraving and etching. Engraving is a process of carving or incising a design onto a hard, usually flat surface, by cutting grooves into it. Etching is a process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal. Both processes are used to create designs, lettering, or images on metal surfaces.