os·te·o·ar·thri·tis 
(ŏs′tē-ō-är-thrītĭs)
(ŏs′tē-ō-är-thrītĭs)n.
A chronic disease characterized by progressive degeneration of the cartilage of the joints, occurring mainly in older persons. Also called degenerative joint disease.
os′te·o·ar·thritic (-thrĭtĭk) adj.
osteoarthritistop: normal joint
bottom: osteoarthritic joint