Source : Webster's Revised Unabridged Dictionary (1913)

Osteosarcoma \Os`te*o*sar*co"ma\, n.; pl. {Osteosarcomata}. [NL.
   See {Osteo-}, and {sarcoma}.] (Med.)
   A tumor having the structure of a sacroma in which there is a
   deposit of bone; sarcoma connected with bone.

Source : WordNet®

osteosarcoma
     n : malignant bone tumor; most common in children and young
         adults where it tends to affect the femur [syn: {osteogenic
         sarcoma}]