, v. i. 1. (Engin.) To have or experience a back fire or back fires; -- said of an internal-combustion engine. [ Webster 1913 Suppl. ]

2. Of a Bunsen or similar air-fed burner, to light so that the flame proceeds from the internal gas jet instead of from the external jet of mixed gas and air. -- Back"-fir`ing, n. [Webster 1913 Suppl.]