osteoarthritis
noun /ˌɒstiəʊɑːˈθraɪtɪs/
/ˌɑːstiəʊɑːrˈθraɪtɪs/
[uncountable] (medical)- a disease that causes painful swelling (= the condition of being larger or rounder than normal) and permanent damage in the joints of the body, especially the hips, knees and thumbs