regnant

The etymology of regnant is fairly straightforward: English speakers borrowed the word sometime around 1600 from Latin. Regnant is derived from the Latin verb regnare, meaning "to reign." Regnare, in turn, traces back to the noun regnum, meaning "reign," which derives from rex, the Latin word for "king." Other descendants of regnum include interregnum ("a period between two successive reigns or regimes"), regnal ("of or relating to a king or his reign"), and even reign itself.