Soviet
early 20th century: from Russian sovet ‘council’.
wiktionary
Borrowed from Russian сове́т(sovét, “council”), from Old Russian borrowed from Old Church Slavonic съвѣтъ(sŭvětŭ, “advice”). Compounded from съ-(sŭ-) + вѣтъ(větŭ, “agreement”), from Proto-Slavic *větъ(“council, talk”). Related words include наве́т(navét), изве́т(izvét), отве́т(otvét), приве́т(privét), обе́т(obét), ве́че(véče), отвеча́ть(otvečátʹ), отве́тить(otvétitʹ), завеща́ть(zaveščátʹ), and совещаться(soveščatʹsja). Probably cognate with Polish witać(“to welcome”).
etymonline
soviet (n.)
1917, from Russian sovet "governing council," literally "council," from Old Russian suvetu "assembly," from su "with" (from *su(n)- "with, together," from PIE *ksun- "with") + vetu "counsel." The whole is a loan-translation of Greek symboulion "council of advisers." As an adjective from 1918.
