Reconstruction:Proto-Slavic/vъnъ

• *vьnъ^[1]

Disputed:

• Meillet, Mladenov: From an amalgamation of Proto-Indo-European *úd (“out”) +‎ *h₂nu (“on, at”), nearly exact cognate with Proto-Germanic *ūtanē (“outside of”). First element akin with Proto-Slavic *vy(d) (“out”), second with Proto-Slavic *na (“on”).
• Vasmer, Zubatý: From reanalysis of Proto-Indo-European *wónm̥ (“alien, external space”), cognate with Sanskrit वन (vána, “wood”).
• Trautmann, Snoj: Related to Proto-Slavic *voňь (“smell, odour”), perhaps from Proto-Indo-European *h₂enh₁- (“to breath”) or from a nasal infix of *h₂weh₁- (“to blow wind”), via semantic development odour → air, athmosphere → open/unbounded space, outside. Cognate with Old Prussian winna (“air”).

*vъ́nъ

1. out, outside, out of reach
2. outdoors

   Synonym: *na dvorě

• *vъnǫtrь (“inside”)

• East Slavic:
  • Old East Slavic: вънъ (vŭnŭ), вонъ (vonŭ)
    • Russian: вон (von), вонки (vonki) (dialectal)
      • → Polish: won
    • Ukrainian: вон (von, “get out!”) (interjection), вонка (vonka)
    • Belarusian: звонку (zvónku, “outside”) (from з- + *вонку)
• South Slavic:
  • Old Church Slavonic: вънъ (vŭnŭ), вьнъ (vĭnŭ)
  • Bulgarian: вън (vǎn), вънка (vǎnka), вонка (vonka)
  • Macedonian: вон (von), вонка (vonka)
  • Serbo-Croatian:

    Cyrillic script: ва̏н

    Latin script: vȁn

  • Slovene: və́n (tonal orthography)
• West Slavic:
  • Old Czech: ven
    • Czech: ven
  • Kashubian: wen
  • Old Polish: wen
  • Old Slovak: von, vonka, vonku
    • Pannonian Rusyn: вонка (vonka), повонку (povonku)
    • Slovak: von, vonku
  • Sorbian:
    • Lower Sorbian: wen
    • Upper Sorbian: won

• Vasmer, Max (1964–1973) “вон”, in Oleg Trubachyov, transl., Этимологический словарь русского языка [Etymological Dictionary of the Russian Language] (in Russian), Moscow: Progress
• Georgiev, Vladimir I., editor (1971), “вън”, in Български етимологичен речник [Bulgarian Etymological Dictionary] (in Bulgarian), volume 1 (А – З), Sofia: Bulgarian Academy of Sciences Pubg. House, →ISBN, page 207