Stage of in this word's full journey.
Where does the word "power" come from? It comes from Latin posse, passing through Old French before entering English (1300s).
Power’s story begins in Latin: posse meant “to be able.” 'to be able'; the same infinitive, through Medieval Latin posse comitatus 'the force of the county', later gave English 'posse'. By 842, the word had taken hold in Old French as podir. Vulgar Latin reshaped posse as *potere; the Oaths of Strasbourg of 842, the oldest text in early French, promise loyalty 'in quant Deus savir et podir me dunat' (as far as God gives me knowledge and power). It reached English by 1300s as power. The 'balance of power' became a stated principle of European diplomacy in the Treaty of Utrecht of 1713. Today, power means the ability or authority to do something; energy supplied for use.