In classical architecture a dentil (from Lat. dens, a tooth) is a small block used as a repeating ornament in the bedmould of a cornice. Dentils are found in classical Greek and Roman architecture and also in later styles, such as Beaux Arts Classicism, Classical Revival, Federal, Georgian Revival, Greek Revival, Neoclassicism, Renaissance Revival, and Second Empire.
The Roman architect Vitruvius (iv. 2) states that the dentil represents the end of a rafter (asser); and since it occurs in its most pronounced form in the Ionic temples of Asia Minor, the Lycian tombs and the porticoes and tombs of Persia, where it represents distinctly the reproduction in stone of timber construction, there is but little doubt as to its origin. The earliest example is that found on the tomb of Darius, c. 500 BC, cut in the rock, in which the portico of his palace is reproduced. Its first employment in Athens is in the cornice of the caryatid portico or tribune of the Erechtheum (480 BC). When subsequently introduced into the bed-mould of the cornice of the Choragic Monument of Lysicrates it is much smaller in its dimensions. In the later temples of Ionia, as in the temple of Priene, the larger scale of the dentil is still retained.