'articular' originates from Latin, specifically the word 'articulāris', where 'articulus' meant 'a small joint' or 'a small part'.

'articulus' in Latin developed into Late Latin 'articulāris' ('of or relating to a joint/part'), passed into Old/Middle French and Middle English forms and eventually became the modern English adjective and noun 'articular' (and the noun plural 'articulars').

Initially it referred to a physical 'joint' or 'small part'; over time the sense extended to 'a part or particular item', leading to modern uses meaning both 'relating to joints' and 'specific details/particulars'.