Source : Webster's Revised Unabridged Dictionary (1913)

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

Source : WordNet®

malacia
     n : a state of abnormal softening of tissue