回火 Traditional form: 回火 Pinyin (reading): huíhuǒ Definitions: to temper (iron) to flare back flareback (in a gas burner) (of an engine) to backfire Characters: 回 - to return, to turn around; a time 火 - fire, flame; to burn; anger, rage Traditional characters: 回 - to return, to turn around; a time 火 - fire, flame; to burn; anger, rage