Reconstruction:Proto-Slavic/bagno

Cognate with Lithuanian bognà (“swamp”), either borrowed from Slavic^[1] or possibly from Proto-Balto-Slavic *bōgnás (as per Miklošič, Holub-Kopečný). Perhaps equivalent to *bagťi (“to ignite, to instigate”) +‎ *-no, ultimately from Proto-Indo-European *bʰeh₃g- (“to bake”). Proposed explanations:

• Brückner, Mladenov, Sławski: In association with the vibrant, auburn coloration of (some) marshes. Parallel to likely cognate Proto-Slavic *bagrъ (“hue”), whence Ukrainian багри́на (bahrýna, “swamp”), Slovak bahurina (“wetland”).
• Machek: In reference to the stagnant water in marshes. Similar to Latin stāgnum (“standing water, pond”).
• Kott: In reference to the odour of decaying vegetation in swamps and marshes, as in Czech bahnina (“marshy, peat odor”).
• Georgiev: Presumably generalized from an earlier meaning “hot spring”, indirectly attested in toponyms Bulgarian Банкя (Bankja), Багнище (Bagnište). Compare analogous toponym Thracian Γέρμων (Gérmōn, “German”) (from Proto-Indo-European *gʷʰer- (“to burn”)).

Derksen alternatively considers a substrate origin (from Pre-Slavic *bʰogʰ-), akin to Dutch bagger (“mud, filth”).

Classically compared with Proto-Germanic *bakiz (“beck, brook”) (alternatively reconstructed as *bakkiz, as in Old Norse bekkr, possibly an i-stem derivative of hypothetical Proto-Indo-European *bʰógʷr̥ (“running water”)) or *bʰeg- (“to bend; wave; bank, shore”). Usually dismissed since Slavic data points towards a standing body of water.

*bagnò n^[1]

1. marsh, swamp, bog

   Synonyms: *bolto, *topь, *tręsina

2. peat, mud, silt

   Synonyms: *kaluga, *gręzь

• *bagňa (ja-stem)

• *bagъno

• *bagnišče (augmentative)
• *bagnina, *bagnьje (“wetland”)
• *bagňakъ (“turf, peat”)
• *bagnьnъ *bagnistъ (“swampy”)

• *bagnъ (“type of aquatic vegetation”)
  • *bagnъka, *bagnьcь (variants)
• *bagrъ (“purple”)
• *bagy (“wetland”)

• East Slavic:
  • Old East Slavic: *багно (*bagno, “peat”)
    • Old Ruthenian: багно (bahno)
      • Belarusian: ба́гна (báhna)
      • Ukrainian: багно (bahno)
    • Russian: багно́ (bagnó) (dialectal)
• West Slavic:
  • Old Czech: bahno
    • Czech: bahno
      • Bohemian (Chod dialect): behno
  • Old Polish: bagno
    • Silesian: bagno
    • Polish: bagno
  • Polabian: bognü
  • Pomeranian:
    • Kashubian: bagno
    • Slovincian: bagnô
  • Slovak: bahno
  • Sorbian:
    • Lower Sorbian: bagno
    • Upper Sorbian: bahno

• Vasmer, Max (1964–1973), “багно́”, in Oleg Trubachyov, transl., Этимологический словарь русского языка [Etymological Dictionary of the Russian Language] (in Russian), Moscow: Progress
• Trubachyov, Oleg, editor (1974), “*bagno”, in Этимологический словарь славянских языков [Etymological dictionary of Slavic languages] (in Russian), numbers 1 (*a – *besědьlivъ), Moscow: Nauka, page 125
• “bogna”, in Lietuvių kalbos etimologinio žodyno duomenų bazė [Lithuanian etymological dictionary database], 2007–2012