'arthritis' originates from New Latin/Greek, specifically the Greek words 'arthron' and '-itis', where 'arthron' meant 'joint' and '-itis' meant 'inflammation'.

'arthritis' changed from the Medieval/Medical Latin usage (influenced by Greek 'arthron' + '-itis') and eventually became the modern English medical term 'arthritis' via New Latin and Anglo-Latin usage.

Initially it meant 'inflammation of a joint'; over time it has come to cover a range of disorders characterized by joint inflammation, pain, and stiffness.