'rheumatism' originates from Greek, specifically the word 'rheuma', where 'rheuein' meant 'to flow'; it passed into Late Latin as 'rheumatismus' and then into English.

'rheumatism' changed from the Late Latin word 'rheumatismus' and the Medieval Latin usage into Middle English and eventually became the modern English word 'rheumatism'.

Initially, it meant 'a flowing (of bodily humors) thought to cause pain', but over time it evolved into the current meaning of 'various painful conditions affecting joints, muscles, or connective tissues'.