firebox

noun

1. the box or chamber containing the fire of a steam boiler, furnace, etc.
2. the furnace of a locomotive, where coal, oil, or other fuel is burned to generate steam.
3. a box or panel with a device for notifying the fire station of an outbreak of fire.
4. Obsolete. a tinderbox.

noun

1. the furnace chamber of a boiler in a steam locomotive
2. an obsolete word for tinderbox