The only free and comprehensive online etymological dictionary of the Spanish language
valer (Verb) "to help;" "to value," "to be worth"
Very late 11th cent. From Latin valere "to be well," "to be strong" From Proto-Italic *wal-ē- 'id.' From Proto-Indo-European *h2u̯lh1-eh1- "to be strong." Perhaps the root *h2u̯lh1- meant "to be big," "to be great."
Also the origin of the toponym Valer, name of a town in Zamora, as well as Valero and Valeros, two towns located in Salamanca.
Indo-European
Romance
Asturian valer, Portuguese valer, Galician valer, Catalan valer, French valoir, Italian valere, Sardinian balere
Italic
Oscan ϝαλε (wale) "farewell," Marrucinian uali 'id.,' Paelignian ual 'id.,' South Picene velaimes "of the best"
Celtic
Old Irish fallnaithir "to rule"
Germanic
Gothic waldan "to rule," Old Norse valda 'id.,' Old High German walten 'id.,' Old English wealdan "to wield power" (English to wield),
Balto-Slavic
Chuch Slavic vladěti "to rule," Russian vladét' "to own," Polish wɫadać "to rule," Slovene vládati 'id.,' Old Prussian weldīsnan "inheritance," Lithuanian veldė́ti "to inherit," Latvian vàldît "to rule"
Tocharian
A wäl "king," B walo 'id.'