osteopetrosis

os·teo·pe·tro·sis

noun \-pə-ˈtrō-səs\

plural os·teo·pe·tro·ses \-ˌsēz\

Definition of OSTEOPETROSIS

: a condition characterized by abnormal thickening and hardening of bone: as a : a rare hereditary disease characterized by extreme density and hardness and abnormal fragility of the bones with partial or complete obliteration of the marrow cavities—called also Albers-Schönberg disease, marble bone disease, marble bones b : avian leukosis of chickens marked by great enlargement and excessive calcification of the long bones especially of the legs and by more or less complete obliteration of the marrow cavities—called also marble bone, marble bone disease