Webster's New World Medical Dictionary

osmolarity, plasma
The osmolarity of blood
plasma, which is a measure of the hydration status
of the body. The plasma osmolarity is sensitive to
changes in hydration status during dehydration and
rehydration.
osseous
Having to do with bone, consisting of
bone, or resembling bone.
ossicle
Any small bone, such as the tiny bones
within the human ear.
ossification 1
The normal process of bone
growth.
2
Hardening, becoming bone-like.
ossify
To harden.
osteitis
Inflammation of the bone.
osteitis deformans
See 
Paget’s disease.
osteitis fibrosa cystica
A condition that is asso-
ciated with excessive parathyroid hormone produc-
tion (hyperparathyroidism), in which bone tissue
becomes soft and deformed. Treatment is directed
toward the underlying parathyroid condition and
relieving any bone pain.
osteo
- Prefix meaning bone, as in osteogenesis
(the production of bone) and osteosarcoma (can-
cer arising in the bone).
osteoarthritis
See 
arthritis, degenerative.
osteoarthropathy
Any disease of the bones and
joints. From 
osteo
-
,
bone + -
arthro
-
,
joint, + 
pathy,
disease.
osteoblast
A cell that makes bone. It does so by
producing a matrix that then becomes mineralized.
Bone mass is maintained by a balance between the
activity of osteoblasts that form bone and other cells
called osteoclasts that break it down.
osteoblastoma
A noncancerous tumor in bone
tissue. Osteoblastomas are small and are seen
most frequently in children and young adults.
Symptoms include pain and bone-mass reduction.
Treatment includes surgery, sometimes followed by
chemotherapy.