'dual-headed' comes from the adjective 'dual' + past-participial adjective 'headed'. 'Dual' ultimately derives from Latin 'dualis', from 'duo' meaning 'two'; 'headed' comes from English 'head' (from Old English 'heafod').

'dual' entered English via Latin 'dualis' (from 'duo') in post-medieval usage, while 'head' evolved from Old English 'heafod' into Modern English 'head'; the compound 'dual-headed' is a Modern English formation combining these elements.

Initially used in literal senses ('having two heads'), the compound has also been used figuratively to describe organizations or systems with two centers of authority; the basic sense of 'two' + 'head' remains consistent.