Wiktionary
Wikipedia
Potestas
Potestas is a Latin word meaning power or faculty. It is an important concept in Roman Law.
Usage examples of "potestas".
If the Church has always asserted with the Apostle there is no power but from God--non est potestas nisi a Deo--she has always through her doctors maintained that it is a trust to be exercised for the public good, and is forfeited when persistently exercised in a contrary sense.
If, said the emperor, or his lawyers for him, the civil power is from God, as it must be, since non est potestas nisi a Deo, the state stands on the same footing with the church, and the imperial power emanates from as high a source as the Pontifical.
Ehlers, Vis atque potestas, quam philosophia antiqua, imprimis Platonica et Stoica in doctrina apologetarum habuerit, 1859.