Fire is the energy, in the form of heat and light, that is released from a chemical reaction. A simple example of a chemical reaction that releases fire is:
Fuel + Oxygen → Water + Carbon dioxide + HEAT + LIGHT
The light from a fire isn’t particularly dangerous to humans but the heat certainly is. For example the typical temperature of a bunsen burner flame is 1500 °C.
I guess that’s why these parents threw their baby from the third floor of a burning building. Check it out (the baby survived by the way):