'arthrosynovitis' originates from Greek and New Latin elements: 'arthro-' from Greek 'arthron' meaning 'joint', 'synovium/synovia' from Medieval Latin (from Greek) meaning 'synovial membrane or fluid', and the suffix '-itis' from Greek '-itēs' meaning 'inflammation'.

'arthron' (Greek) + 'synovia' (Medieval/Latin medical usage) combined with the Greek-derived suffix '-itis' produced medical compound forms in New Latin/Modern medical English; these elements were joined to form the modern term 'arthrosynovitis' in medical literature.

Initially the parts meant 'joint' + 'synovial membrane/fluid' + 'inflammation'; over time they were directly combined into a single medical term whose meaning remains the inflammation of the joint's synovial lining.