Furnace and Gas ring

Furnace noun - An enclosed chamber in which heat is produced to heat buildings, destroy refuse, smelt or refine ores, etc..

Gas ring and furnace are semantically related in hob topic. In some cases you can use "Gas ring" instead a noun "Furnace".

Gas ring noun - Gas burner consisting of a circular metal pipe with several small holes through which gas can escape to be burned.

Furnace and gas ring are semantically related in hob topic. Sometimes you can use "Furnace" instead a noun phrase "Gas ring".