Triglyph

Triglyphs are decorative rectangular tablets set in the frieze, the horizontal strip between the architrave and the pediment. The triglyphs alternate space on the frieze with decorative blocks known as metopes. Each triglyph features two full vertical grooves, or channels, and two half-channels called chamfers. Triglyphs echo the verticality of the columns below while serving to frame the sculptures and paintings presented in the metopes. They also have a structural function, providing support for the roof.

The Doric Order evolved from the post-and-beam wooden construction of Ancient Greece, and triglyphs are vestiges of the ends of the wooden beams, which were often notched in three separate places to better hide their rough finish in shadow.

The teethlike elements below the triglyphs are guttae, which help funnel water away from the building's surface.