What is the meaning of Sweat_hole?

An opening in the skin through which sweat is excreted; pore.

A large hole in the ground, heated with a fire, into which a sick person is brought wrapped in blankets (once the fire is removed), with a jug of water for making steam, the whole covered by an awning to hold the steam in; an underground sweat lodge.

An uncomfortably hot, enclosed, space.

Source: wiktionary.org