'armrest' originates from English, formed as a compound of the words 'arm' and 'rest', where 'arm' referred to the human limb and 'rest' meant 'a place or means of resting'.

'armrest' developed in Modern English as a compound from Old English elements: 'arm' (from Old English 'earm') + 'rest' (from Old English 'ræst'), becoming the modern compound 'armrest'.

Initially, it meant 'a rest for the arm'; this basic, literal sense has remained largely unchanged into contemporary usage.