'acromioclavicular' originates from Latin, specifically the words 'acromion' and 'clavicula,' where 'acromion' referred to the outermost point of the shoulder blade and 'clavicula' meant 'little key' or 'collarbone.'

'acromion' and 'clavicula' were combined in medical terminology to describe the joint between the shoulder blade and collarbone, eventually forming the modern English term 'acromioclavicular.'

Initially, it referred specifically to the anatomical parts, and this meaning has largely remained the same in modern medical usage.