The Collaborative International Dictionary of English v.0.48:
Diaglyph \Di"a*glyph\, n. [Gr. ? to engrave; dia` through + ? to carve.] An intaglio. --Mollett. DiaglyphicWordNet (r) 3.0 (2006):
diaglyph n 1: glyptic art consisting of a sunken or depressed engraving or carving on a stone or gem (as opposed to cameo) [syn: intaglio, diaglyph]