A somewhat dated or literary term for an oven; in modern Japanese, オーブン is far more common. Still encountered in older texts or traditional contexts.
See also: オーブン
My grandmother used to bake bread in an oven.
This old cookbook explains how to use an oven in detail.
Compound of 天 (ten, 'heaven') and 火 (hi, 'fire'), possibly referring to the heat from above in a traditional oven. The exact historical derivation is uncertain.