15th cent. A learned borrowing from Latin quietus 'id.' The native word was quedo. From quiescere "to rest." From quies "rest" (see quitar) and -escere, an inchoative verb-forming suffix (see -ecer).
Romance: Western Vulgar Latin: Asturian quietu, Portuguese quieto, Galician quieto, French quiet, Italian quieto ; Eastern Vulgar Latin: Romanian cet ; Sardinian: achietu