Source : Webster's Revised Unabridged Dictionary (1913)

Convexity \Con*vex"i*ty\, n.; pl. {Convexities}. [L. convexitas:
   cf. F. convexit['e].]
   The state of being convex; the exterior surface of a convex
   body; roundness.

         A smooth, uniform convexity and rotundity of a globe.
                                                  --Bentley.