1. To burn violently, or to make something burn in a very strong way with great heat and intense light: Timothy bought some maple wood, which he knew would deflagrate wonderfully in his fireplace in the living room at home.

The grasslands were so dry from the long hot summer that they suddenly deflagrated when someone threw out his or her burning cigarette while driving through the country.

2. To cause to burn with sudden and sparkling combustion, as by the action of intense heat: The fireworks were deflagrated on Independence Day in the big town square, presenting spectacular colors and forms in the sky.