The Collaborative International Dictionary of English v.0.48:

Osteomalacia \Os`te*o*ma*la"ci*a\, n. [NL., fr. Gr. 'oste`on
   bone + ? softness.] (Med.)
   A disease of the bones, in which they lose their earthy
   material, and become soft, flexible, and distorted. Also
   called malacia.
   [1913 Webster]

WordNet (r) 3.0 (2006):

osteomalacia
    n 1: abnormal softening of bones caused by deficiencies of
         phosphorus or calcium or vitamin D