entasis

1. (architecture) A slight convex curvature introduced into the shaft of a column for aesthetic reasons, or to compensate for the illusion of concavity.Examples: "It was simply the curve of the entasis, approximating infinitely near to a catenary or to a very flat hyperbola. He could not definitely say whether it was one or the other, but it was nearer to these curves than to the old-fashioned straight line."; "The entasis varies in different temples and is not found in some, as, for instance, the temple of Athena Nike and in the east portico of the Erechtheum."; "Entasis occurred a thousand years earlier in the Sarsen stones at Stonehenge in southern England.[…]Entasis is also present in Egyptian obelisks and in the vertical fins of the radiator grill of the Rolls-Royce automobile."countableuncountable