Gutta in the context of "Taenia (architecture)"

The Doric order is one of the three orders of ancient Greek and later Roman architecture; the other two canonical orders were the Ionic and the Corinthian. The Doric is most easily recognized by the simple circular capitals at the top of the columns. Originating in the western Doric region of Greece, it is the earliest and, in its essence, the simplest of the orders, though still with complex details in the entablature above.

The Greek Doric column was fluted, and had no base, dropping straight into the stylobate or platform on which the temple or other building stood. The capital was a simple circular form, with some mouldings, under a square cushion that is very wide in early versions, but later more restrained. Above a plain architrave, the complexity comes in the frieze, where the two features originally unique to the Doric, the triglyph and gutta, are skeuomorphic memories of the beams and retaining pegs of the wooden constructions that preceded stone Doric temples. In stone they are purely ornamental.

Triglyph is an architectural term for the vertically channeled tablets of the Doric frieze in classical architecture, so called because of the angular channels in them. The rectangular recessed spaces between the triglyphs on a Doric frieze are called metopes. The raised spaces between the channels themselves (within a triglyph) are called femur in Latin or meros in Greek. In the strict tradition of classical architecture, a set of guttae, the six triangular "pegs" below, always go with a triglyph above (and vice versa), and the pair of features are only found in entablatures of buildings using the Doric order. The absence of the pair effectively converts a building from being in the Doric order to being in the Tuscan order.

The triglyph is largely thought to be a tectonic and skeuomorphic representation in stone of the wooden beam ends of the typical primitive hut, as described by Vitruvius and Renaissance writers. The wooden beams were notched in three separate places in order to cast their rough-cut ends mostly in shadow. Greek architecture (and later Roman architecture) preserved this feature, as well as many other features common in original wooden buildings, as a tribute to the origins of architecture and its role in the history and development of man. The channels could also have a function in channeling rainwater.