Reconstruction:Proto-Slavic/sьčava - Wiktionary, the free dictionary

• (sorrel): *sьčavъ m, *sьčavь m, *sьčavьjь m, *sьčьjь m, *sьčavьľь m, *sьčaľь m, *sьčakъ m, *sьčavьje n, *sьčaga f, *sьčagъľь m
• (tanning liquor): possibly already *sьčavina

From *sьkati, *sьcati (“to piss”), because one tanned with urine, +‎ *-ava.

*sьčava f

1. tanning liquor
2. juice from any plant under the condition that it is somehow pungent
3. sorrel, dock

• *sьčavьnъ (“sour, pungent, tanning”)
  • Old East Slavic: щавьныи (ščavĭnyi, “sour”)^[1]
    • Middle Russian: щавьнь (ščavʹnʹ, “sour”) (15-17ᵗʰ cent.)

• East Slavic:
  • Belarusian: шча́ўе (ščáŭje, “sorrel”); шчаў (ščaŭ), шчагу́н (ščahún) (dialectal)
  • Russian: ща́ве́ль (ščávélʹ, “sorrel”); щаве́й (ščavéj) (dialectal)
  • Ukrainian: щаве́ль (ščavélʹ, “sorrel”); ща́ва́ (ščává), щаве́й (ščavéj), щаві́й (ščavíj), ща́вка (ščávka), щаву́х (ščavúx), щав'я́н (ščavʺján), ща́ва́ (ščává, “also means a kind of sour liquid for preparing clothes for dyeing and sour mineral water”) (dialectal)
• South Slavic:
  • Old Church Slavonic:

    Old Cyrillic script: щавъ m (štavŭ, “sorrel”)

    Glagolitic script: ⱋⰰⰲⱏ m (štavŭ, “sorrel”)

  • Bulgarian: ща́ва (štáva, “tanning liquor, tanning acid”), also щавина (štavina, “sorrel”) in this meaning, щаве́л (štavél, “sorrel”), and ще́ва (štéva) is an unidentified kind of poisonous plant
  • Macedonian: штава (štava, “tanning liquor”)
  • Serbo-Croatian:

    Latin script: štȁva, štȁvina (“tanning liquor”) (archaic, regional), štávalj, štávelj; štav, štavje, ščavje, šćavlje, štavlje, štavlja, štavljak, staglina, šavje (“sorrel”) (dialectal)

    Cyrillic script: шта̏ва, шта̏вина (“tanning liquor”) (archaic, regional), шта́ваљ, шта́вељ; штав, штавје, шчавје, шћавље, штавље, штавља, штављак, стаглина, шавје (“sorrel”) (dialectal)

  • Slovene: ščȃv, ščávje (“sorrel”), ščáva (“sorrel; swill, slops, pig fodder”), ščávəlj (“sorrel”), ščȃvje (“sorrel”)
• West Slavic:
  • Old Czech: ščáva
    • Czech: šťáva (“sap, juice, gravy”), also šťava, šťavina in this meaning, šťavel (“oxalis”), šťovík (“sorrel”)
  • Old Polish: szczaw
    • Polish: szczaw (“sorrel”) of which the genitive is soft szczawiu, szczawa (“sour natural mineral water”), szczawik (“sorrel; oxalis”), szczal, szczagiel, szczój (“sorrel”), szczel (“urine”)
  • Slovak: šťáva, šťava (“sap, juice”), štiava (“sap; sorrel”), šťav, štiav, štiaľ, ščav (“sorrel”) (dialectal)
    • → Hungarian: csáva (“tanning liquor”)
  • Pomeranian:
    • Kashubian: szczôw, szczawa (“sorrel”)
    • Slovincian: szczawa (“whey; sorrel”)
  • Sorbian:
    • Lower Sorbian: šćaw (“sorrel”)
    • Upper Sorbian: šćehel (“sorrel”)

• Boryś, Wiesław (1976) Etymologie słowiańskie i polskie. Wybór studiów z okazji 45-lecia pracy naukowej‎^[1] (in Polish), Warsaw: Slawistyczny ośrodek wydawniczy, published 2007, →ISBN, pages 53–70 = Rocznik Slawistyczny XXXVII, pages 47–63
• Melnychuk, O. S., editor (1982–2012), “ща́ва́”, in Етимологічний словник української мови [Etymological Dictionary of the Ukrainian Language] (in Ukrainian), Kyiv: Naukova Dumka