if fire isn’t a solid liquid or a gas then what is it ?

Question: if fire isn't a solid liquid or a gas then what is it ?
- Keywords:
  fire,
  gas,
  liquid,
  solid
Asked by 491utec48 to Alison, Hannah, Jonny, MarthaNari, Paul on 19 Jun 2015.
- Paul Brack answered on 19 Jun 2015:
  
  It’s a chemical reaction happening between several gases – here’s a great answer: http://engineering.mit.edu/ask/fire-solid-liquid-or-gas

Question: if fire isn't a solid liquid or a gas then what is it ?