Latin aqua 'water' (updated)

Latin aqua 'water' < *akw-ā (f.) is an interesting word with correspondences in Germanic *áxwō 'river' (Gothic ahwa, Old High German aha) as well as Celtiberian akua,  whose meaning is probably 'river' (cfr. tar akuai 'across the river' in Botorrita III¹). Contrarily to what many scholars think, its original meaning isn't 'water' but 'river'² and belongs to the Old European Hydronymy (OEH), a corpus first studied by Hans Krahe and more recently by Francisco Villar and which represents an older form of IE than the historically attested languages³.  

Apparently, *akʷā would be a derivated noun from the adjective *aku- 'quick, fast', found in Latin acupedius 'swift of foot' and accipiter 'hawk', the latter with cognates in Greek ōkýpteros, literally meaning 'swift flyer' (ōkýs 'swift', pterón 'wing'), and Sanskrit āśu-pátvan- 'flying swiftly'⁴. These correspondences suggest Paleo-European *aku- would correspond to late IE *ōḱu- 'quick' > Latin ōcior.

On the other hand, the geminate stop in accipiter would be the result of a sound shift -kʷ- > -kk- which I call Kretschmer's Law and of which are examples in Italoid (e.g. the Lusitanian theonym Iccona) and Celtic (e.g. *sukko- 'pig'). There're also traces of it in Vulgar Latin 'water', as reflected in the Appendix Probi (aqua non acqua).

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¹ P. de Bernardo Stempel (2007): Water in the Botorrita Bronzes and Other Inscriptions, in Palaeohispanica 7, pp. 55-69.
² Despite so, it has been compared it to other 'water' words, both within the IE family and oustide, even up to the point of building upon it a "global etymology" (Ruhlen).

³ More specifically, its agglutinative morphology would correspond to the "IE I (pre-flexional)" stage proposed by Francisco Rodríguez Adrados. Of course, Vennemann's proposal of OEH being related to Basque must be rejected.

⁴ M. de Vaan (2008): Etymological Dictionary of Latin and the Other Italic Languages, p. 21.

Gaulish *santikā 'ladle; milking vessel' (updated)

Gascon sanja, sansha, santja, sòntja, shansha, sancha, Aragonese sancha and dialectal Catalan sanxa (Cerdanya) designate a milking vessel carved in wood, often made by hollowing out a tree trunk¹. On the other hand, dialectal Basque xantxa (L, Z), xaiñtxa (Z) designates a milking vessel with a long metal handle (kopetxa), and in the latter also 'ladle' (golhare), a meaning which in my opinion would be the original one².

Although the Gaulish origin of this word seems undeniable, a Celtic etymology is more dubious. For example, Matasović proposes a Celtic femenine *sϕanjā corresponding to the masculine *sϕenjo- > Old Irish sine 'teat'³, in turn derived from IE *spen-, which is phonetically unacceptable, among other things because Celtic *sϕ- gives s- in Goidelic but f- in Britonic and probably also in Gaulish. For the same reason, Hubschmid's protoform *sand-ikā from IE *spn̥dh- 'bucket'⁴ can't be accepted, although Celtic *sϕondā would be the origin of Romansh s(u)onna 'bucket', probably a Lepontic loanword.

Following Coromines⁵, I'd propose a Gaulish protoform *santi-kā as a Baltoid loanword corresponding to Baltic *samti-/semti- > Lithuanian sámtis 'spoon, ladle', sémti 'to pump, to scoop (a liquid)', from an IE root *semH- 'to pump, to scoop (a liquid)' also found in Latin sentīna 'bilge; sewer, drainage' and cognate to Altaic *ʃŏ́mo 'to dive; to summerge; to scoop (a liquid)' (EDAL 2193) > Turkic *tʃo:(m)- 'to diver; to swim; to scoop (a liquid); to immerse, to dip' (Turkish čömče 'spoon'⁶). On the other hand, Etruscan śanti (Tabula Capuana) probably designated some kind of vessel.

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¹ G. Rohlfs (1970): Le Gascon. Etudes de phylologie pyrénéenne, § 59. It's likely the same kind of vessel called kaiku in Basque.

² The oldest European metal ladlers are from the Hallstatt culture of the Early Iron Age.

³ R. Matasović (2009): Etymological Dictionary of Proto-Celtic, p. 333.

⁴ J. Hubschmid (1951): Alpenwörter. Ursprungs und vorromanischen Romanischen, p. 61.

⁵ DECLC, p. 667-668.

⁶ J. Hubschmid (1955): Schläuche und Fasser, p. 107, quotes čamča, čumča with a diminutive suffix -ča.