lordosis

from WordNet (r) 3.0 (2006)

lordosis
    n 1: an abnormal inward (forward) curvature of the vertebral
         column [syn: {lordosis}, {hollow-back}]

from The Collaborative International Dictionary of English v.0.48

Lordosis \Lor*do"sis\, n. [NL., fr. Gr. ?, fr. ? bent so as to
   be convex in front.] (Med.)
   (a) A curvature of the spine forwards, usually in the lumbar
       region.
   (b) Any abnormal curvature of the bones.
       [1913 Webster]