Arnold

"sea eagle," from Old English earn "eagle," from Proto-Germanic *aron-, *arnuz "eagle" (source also of Old High German arn, German Aar, Middle Dutch arent, Old Norse örn, Gothic ara "eagle"), from PIE root *or- "great bird" (source also of Greek ornis "bird," Old Church Slavonic orilu, Lithuanian erelis, Welsh eryr "eagle"). The Germanic word also survives in the first element of names such as Arnold and Arthur.

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."