entasis

Definition of Entasis in English :

1. entasis

a slight convexity in the shaft of a column; compensates for the illusion of concavity that viewers experience when the sides are perfectly straight

WordNet Lexical Database for English. Princeton University. 2010.

Entasis

noun plural -ses (-siːz)

1.

a slightly convex curve given to the shaft of a column, pier, or similar structure, to correct the illusion of concavity produced by a straight shaft

2. Also called: entasia (ɛnˈteɪzɪə ) physiology

an involuntary or spasmodic muscular contraction

nounWord forms: plural ˈentaˌses (ˈɛntəˌsiz ; enˈtəsēzˌ)

Architecture

a slight, convex swelling in the shaft of a column: it prevents the illusion of concavity produced by a perfectly straight shaft

n. pl. en·ta·ses (-sēz′)

A slight convexity or swelling, as in the shaft of a column, conventionally employed especially in classical architecture.