Entasis

In architecture, entasis is the application of a convex curve to a surface for aesthetic purposes. Its best-known use is in certain orders of Classical columns that curve slightly as their diameter is decreased from the bottom upwards. In the Hellenistic period, some columns with entasis are cylindrical in their lower parts. Some Roman columns are "cigar-shaped", with the widest point some distance above the foot.

The word derives from the Greek word εντείνω (enteino), "to stretch or strain tight".

Examples

Probably the first use of entasis was in the construction of the Egyptian pyramids, but it can also be observed in Classical period Greek column designs, for example in the Doric-order temples in Segesta, Selinus, Agrigento and Paestum. It was used less in Hellenistic and Roman period architecture. The Roman temples built during these periods were higher than those of the Greeks, with longer and thinner columns. Chinese carpenters of the Song Dynasty followed the designs in the AD 1103 Yingzao Fashi (Treatise on Architectural Methods or State Building Standards) which specified straight columnns or with an entasis on the upper third of the shaft. Noted architects such as the Renaissance master Andrea Palladio also used it in their buildings.