The only free and comprehensive online etymological dictionary of the Spanish language
volver (Verb) "to return"
12th cent. From Latin volvere "to turn." From Proto-Italic *welo-e/o- "to cause to go around." From Proto-Indo-European *u̯el-u̯- "to wind;" "to cover."
Portuguese volver, Galician volver, Catalan vogir, Italian volgere, Aromanian volbu, Romanian holba
Old Irish fillid "to bend," Middle Breton goalenn "green twig"
Gothic walwjan "to revolve," Old English wealwian 'id.'
Old Church Slavonic valiti "to roll"
Ancient Greek εἰλύω (eilyo) "I wind"
Armenian egel "he turned"
A walyi "worms," B wäl- "to curl"
vos (Personal Pronoun) "you"
12th cent. Originally meaning (pl.) "you." The creation of vosotros (12th cent.) as an emphatic form of vos gradually led to vos being restricted to the singular sense, beginning in the 15th cent. From Latin vos 'id.' From Proto-Italic *wōs 'id.' From Proto-Indo-European *u̯ōs "to you," accusative of *i̯uH.
Portuguese vós, Galician vós, Catalan vós, French vous, Italian voi, Aromanian voi, Romanian voi
vosotros (Personal Pronoun) (pl.) "you"
12th cent. Originally an emphatic form of vos. From vos and otro.
Galician vosoutros, Catalan vosaltres, French vous autres, Italian voialtri
voy, vaya, va-, vaya- Present and imperative conjugation forms in verb ir.
Old Spanish vo, vaya, va-, vaya- respectively, except Spanish vamos and vais were drawn from Old Spanish vamos, 1st person plural present subjunctive, and vades, 2nd person plural present subjunctive, which replaced Old Spanish imos and ides in the 16th cent. through a process of regularization. However, the archaic sense of vamos is preserved as the imperative, which was left unaffected by this development.

All forms are from Latin vadere "to go," "to hurry." Latin vadere is from Proto-Italic *wāþ-e/o- 'id.' A thematic present from Proto-Indo-European *u̯eh2dh- 'id.'
The evolution of this verb into Spanish is curious. Evidently, after the interior -d- was lost in Vulgar Latin, stress was maintained on the initial vowel that made it resistant to regular phonological changes in early Spanish (e.g., Latin vadis "you go" yields vas and not **ves) (see also Penny 2002).

Subjunctive forms were remodeled after other verbs ending in -aya (cf. haber).

For the evolution of Old Spanish vo to modern Spanish voy, see -oy.
voz f. (Noun) "voice"
12th cent. From Latin vocem, accusative of vox 'id.' From Proto-Italic *wōkws 'id.' From Proto-Indo-European *u̯ōkw-s
Asturian voz, Portuguese voz, Galician voz, Catalan veu, French voix, Italian voce, Aromanian boatsi, Romanian voce, Sardinian boghe
Umbrian suboco "invocation" (lit. 'low-voice')
Ancient Greek ὀπ- (óp-) "voice"
Sanskrit vā́k "voice," Old Avestan vāxš 'id.'
A wak "voice," wek 'id.'
vuelo m. (Noun) "flight"
14th cent. From volar.
vuestro (Possessive Pronoun) "your"
12th cent. From Latin vostrum, accusative of voster 'id.' From Proto-Italic *wos-tero- 'id.' From Proto-Indo-European *u̯s-tero- 'id.'
Asturian vuestru, Portuguese vosso, Galician voso, Catalan vostre, French votre, Italian vostro, Aromanian vostru, Romanian vostru, Sardinian bostru
vulgar (Adjective) "vulgar;" "common"
15th cent. From Latin vulgaris "common," "plain," from vulgus "common people," "crowd" (see vulgo).
Portuguese vulgar, Galician vulgar, Catalan vulgar, French vulgar, Italian volgare, Romanian vulgar
vulgo m. (Noun) "common people," "folk"
14th cent. From Latin vulgus 'id.,' earlier volgus. Of unknown origin.
Portuguese vulgo, Galician vulgo, Italian volgo, Romanian vulg
whisky, güisqui m. (Noun) "whisky"
Borrowed from English whisky, itself borrowed from Irish uisce beatha "water of life," a calque of a Latin term aqua vitæ for an alcoholic drink. For the etymology of aqua, see agua; for vitæ, see vida.