1911 Encyclopædia Britannica/Triglyph

TRIGLYPH (Gr. τρεῖς, three, and γλυφή, an incision or carving), an architectural term for the vertically channelled tablets of the Doric frieze, so called because of the angular channels in them, two perfect and one divided—the two chamfered angles or hemiglyphs being reckoned as one. The square sunk spaces between the triglyphs on a frieze are called metopes.