noun, masculine/aɾkaˈismo/plural: arcaísmos
archaism (an archaic word or expression)
Borrowed from New Latin archaismus, from Ancient Greek ἀρχαϊσμός (arkhaïsmós, “an antiquated phrase or style”), from ἀρχαίζω (arkhaízō, “to model one's style upon that of ancient writers”), from ἀρχαῖος (arkhaîos, “old, ancient”), from ἀρχή (arkhḗ, “beginning”), from ἄρχω (árkhō, “to begin”), from Proto-Indo-European *h₂ergʰ- (“to begin, rule, command”).