Intaglio covers metal-plate techniques like etching, drypoint, engraving, aquatint, and mezzotint amoong others.

The word comes from the Italian intagliare, to incise, and that's the operating principle: the lines or areas holding ink sit below the surface of the plate, not on it. After inking and wiping back, damp paper is applied to the surface and the plate is run through the press. The paper is forced into the grooves and picks up the ink lying below the surface.