rheumatologyPronunciation: /ˌruːməˈtɒlədʒi/Definition of rheumatology noun [mass noun] Medicine the study of rheumatism, arthritis, and other disorders of the joints, muscles, and ligaments. Derivatives rheumatologicalPronunciation: /-təˈlɒdʒɪk(ə)l/ adjective rheumatologist noun rheumatology in other Oxford dictionaries Definition of rheumatology in the US English dictionary