'arthritism' originates from New Latin/Modern medical formation, specifically from the word 'arthritis' plus the suffix '-ism', where 'arthr-' (from Greek) meant 'joint' and '-itis' meant 'inflammation', and '-ism' forms a condition or state.

'arthritism' developed from Greek 'arthron' (joint) into Medieval/Modern Latin 'arthritis' (joint inflammation), and the English formation 'arthritis' later produced the rare derivative 'arthritism' by adding the suffix '-ism' to denote the condition or state.

Initially related directly to the Greek-root sense of 'joint inflammation', the term came to be used in English to denote the condition of arthritis or arthritis-like conditions, sometimes in a broader or less technical sense than 'arthritis'.