This Proto-Slavic entry contains reconstructed terms and roots. As such, the term(s) in this entry are not directly attested, but are hypothesized to have existed based on comparative evidence.

From a k-extension of Proto-Indo-European *tenH- (“to contract, to stretch”), akin to Lithuanian tánkus (“thick”), Proto-Germanic *þinhtaz (“tight, dense”).

*tǫ̀ča f

1. (perhaps originally) condensation, cumulation, thickening
2. (by abstraction) precipitation

   → downpour, inundation, storm (South Slavic)

   → rainy cloud (East Slavic)

   Synonym: *xmara

   → rainbow (West Slavic)

   Synonyms: *dǫga, *radǫga (East Slavic)

• *tǫčiti (sę) (“to precipitate”)
• *tǫčьnъ (“abundant, copious”)

• *tękati, *tęknǫti (“to captivate, to excite”)
• *tękъ (“appetite, captivation”)

• East Slavic:
  • Old East Slavic: ту́ча (túča)
    • Russian: ту́ча (túča)
    • Ukrainian: ту́ча (túča)
• South Slavic:
  • Old Church Slavonic:

    Old Cyrillic script: тѫча (tǫča)

    Glagolitic script: ⱅⱘⱍⰰ (tǫča)

  • Bulgarian: ту́ча (túča), тъ́нча (tǎ́nča) (dialectal)
  • Serbo-Croatian:

    Cyrillic script: ту̏ча

    Latin script: tȕča

  • Slovene: tọ́ča (tonal orthography)
• West Slavic:
  • Polabian: tǫco
  • Old Polish: tęcza
    • Polish: tęcza
  • Sorbian:
    • Lower Sorbian: tuca
    • ⇒ Upper Sorbian: tučel, tučatka

• Vasmer, Max (1964–1973) “туча”, in Oleg Trubachyov, transl., Этимологический словарь русского языка (in Russian), Moscow: Progress
• “tankus”, in Lietuvių kalbos etimologinio žodyno duomenų bazė , 2007–2012