'Incurvation' definitions:

Definition of 'incurvation'

noun

A shape that curves or bends inward [syn: concave shape, concavity, incurvation, incurvature]

noun

The action of creating a curved shape

From: GCIDE

Incurvation \In`cur*va"tion\, n. [L. incurvatio: cf. F. incurvation.] [1913 Webster]
1. The act of bending, or curving. [1913 Webster]
2. The state of being bent or curved; curvature. [1913 Webster]
An incurvation of the rays. --Derham. [1913 Webster]
3. The act of bowing, or bending the body, in respect or reverence. "The incurvations of the knee." --Bp. Hall. [1913 Webster]