vodka

English vodka was borrowed from Russian во́дка (vódka), which combines вода́ (vodá, "water") with the diminutive suffix -ка (-ka). Russian вода́ itself descends through Old East Slavic and Proto-Slavic *voda back to Proto-Indo-European *wódr̥, "water."

V. Pokhlyobkin's research suggests the name arose from phrases about diluting the pure distilled spirit, replacing an older Russian term, хле́бное вино́ ("grain wine"), that had described the drink before.

The same PIE root *wed- that gave us вода́ also underlies English water, and it's cognate with Sanskrit उदक (udaka) and Ancient Greek ὕδωρ (húdōr), the source of English hydro-.