late 15c., from French valeureux, from valeur (see valor). Related: Valorously; valorousness.
Proto-Indo-European root meaning "to be strong."
It forms all or part of: ambivalence; Arnold; avail; bivalent; convalesce; countervail; Donald; equivalent; evaluation; Gerald; Harold; invalid (adj.1) "not strong, infirm;" invalid (adj.2) "of no legal force;" Isold; multivalent; polyvalent; prevalent; prevail; Reynold; Ronald; valediction; valence; Valerie; valetudinarian; valiance; valiant; valid; valor; value; Vladimir; Walter; wield.
It is the hypothetical source of/evidence for its existence is provided by: Latin valere "be strong, be well, be worth;" Old Church Slavonic vlasti "to rule over;" Lithuanian valdyti "to have power;" Celtic *walos- "ruler," Old Irish flaith "dominion," Welsh gallu "to be able;" Old English wealdan "to rule," Old High German -walt, -wald "power" (in personal names), Old Norse valdr "ruler."
c. 1300, "body or host of knights; knighthood in the feudal social system; bravery in war, warfare as an art," from Old French chevalerie "knighthood, chivalry, nobility, cavalry, art of war," from chevaler "knight," from Medieval Latin caballarius "horseman," from Latin caballus "nag, pack-horse" (see cavalier).
From late 14c. as "the nobility as one of the estates of the realm," also as the word for an ethical code emphasizing honor, valor, generosity and courtly manners. Modern use for "social and moral code of medieval feudalism" probably is an 18c. historical revival.