stadtholder
The chief provincial magistrate, military commander, and, as a member of the House of Orange, highest-ranking noble in the Dutch Republic, who often served as a de facto head of state alongside the States General; the position became hereditary in 1747
historical
In keeping with the decentralization principe, each province had, in any case, to appoint its own Stadholder, who might not necessarily be the same prince of Orange, or stem from the dynastic trunk. (…) Sovereignty, it was affirmed, lay with the States General, whose bidding the Stadholder was to do as once he had done the king’s.
An office formerly held by Danish and Swedish officials, best translated as governor-general.
historical
Where it comes from
Partial calque of Dutch stadthouder (superseded), stadhouder (literally “placeholder”), from Middle Dutch stathouder, itself a calque of Medieval Latin locum tenēns. Doublet of locum tenens and lieutenant.
Adapted from the Wiktionary entry stadtholder (CC BY-SA 4.0).