Answer:
Arthritis is inflammation of a joint. Bursitis is inflammation of a bursa, which is a friction-reducing structure found near certain joints. Rheumatism is a lay term that may refer to inflammation or discomfort in any of the connective tissues. The prefix artho- means joint and the suffix -itis means inflammation so putting them together you get arthritis which means inflammation of a joint.
Arthritis is inflammation of a joint.