arthritis: [16] Greek árthron meant ‘joint’ (it is used in various technical terms in biology, such as arthropod ‘creature, such as an insect, with jointed limbs’). It came from the Indo-European root *ar- ‘put things together, join, fit’, which also produced Latin artus ‘limb’ (source of English article) and English arm, as well as art. The compound arthritis is a Greek formation (-itis was originally simply an adjectival suffix, so arthritis meant ‘of the joints’ – with ‘disease’ understood; its application to ‘inflammatory diseases’ is a relatively modern development); it reached English via Latin. => arm,