wildfire

1. (historical) Greek fire.countablehistoricaluncountable

2. (dermatology) A spreading disease of the skin, particularly erysipelas.countableuncountable

3. (figuratively) Something that acts or spreads quickly and uncontrollably.Examples: "So, it appears a revolution has happened and a very unexpected one. Of course it was only a matter of time before it happened. With WiFi connectivity spreading faster than wildfire and a laptop or tablet in one’s bag, what’s the point of a mobile nowadays?"; "“It was my own personal watch and I wanted to change the face,” she said in an interview during a recent business trip to New York. “I started wearing it, and it was wildfire — everybody wanted one.”"countablefigurativelyuncountable