'twin-headed' is a modern English compound formed from 'twin' + 'headed', where 'twin' means 'twofold, paired' and 'headed' is the adjective form of 'head' (having a head).

The compound arose by combining the adjective 'twin' (from Old English roots) with 'headed' (from 'head' + adjectival -ed). 'Twin' comes from Old English 'twinna'/'twinn' meaning 'double' and 'head' comes from Old English 'heafod'; the compound construction reflects a long-established pattern in English of joining an adjective or numeral with 'headed' (e.g., 'single-headed', 'many-headed').

Initially the elements denoted literal physical features ('two' + 'head'), and while the primary meaning remains 'having two heads', the term has also been extended figuratively to describe organizations or systems with two centers of authority.