The Collaborative International Dictionary of English v.0.48:

Incurvity \In*cur"vi*ty\ ([i^]n*k[^u]"v[i^]*t[y^]), n. [From L.
   incurvus bent. See Incurvate.]
   A state of being bent or curved; incurvation; a bending
   inwards. --Sir T. Browne.
   [1913 Webster]