The story
Partial calque of German Sitzbad (“idem.”, literally “sit bath”), from Sitz (“seat”) + Bad (“bath”), from sitzen (“to sit”).
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A hydrotherapeutic bath taken in a sitting position. Full definition →
Partial calque of German Sitzbad (“idem.”, literally “sit bath”), from Sitz (“seat”) + Bad (“bath”), from sitzen (“to sit”).
Etymology from Wiktionary, CC BY-SA 4.0.