open hearth

Short definition from Wiktionary

Noun

1. 1
   An open hearth furnace (open-hearth furnace).
2. 2
   A home hearth comprising a hearthstone alone, as opposed to one comprising a hearthstone and fireplace or oven.

Adjective

1. 1
   Alternative form of open-hearth (open compound attributive form)
2. 2
   Describing a reverberatory furnace used to make steel, usually in mass-produced quantities.
3. 3
   Designating the steel so produced.
4. 4
   Describing an open hearth in the home, especially in premodern centuries when such hearths were more common.