plunge bath

noun2

1. •
   A tub or pool large enough to immerse the entire body.

   • The Physical Remains Due to the extensive demolition of this part of the structure almost nothing now remains above the fumace to the east of the caldarium, where the plunge bath must have stood. — 2001
2. •
   Immersion of the entire body in water by plunging.

   • A physician should well examine his patient's powers and be well certified of the integrity and strength of his brain circulation, before he orders the plunge bath. — 1844