1. noun /faɪə(ɹ),faɪɚ/
a) A (usually self-sustaining) chemical reaction involving the bonding of oxygen with carbon or other fuel, with the production of heat and the presence of flame or smouldering.
We sat around the fire singing songs and telling stories.
b) Something that has produced or is capable of producing this chemical reaction, such as a campfire.
There was a fire at the school last night and the whole place burned down.
2. verb /faɪə(ɹ),faɪɚ/
a) To set (something) on fire.
"Fired the house. It was the only way to cover my trail—and no doubt it was insured."
b) To heat without setting on fire, as ceramic, metal objects, etc.
It was long a question of debate, whether the burning of the South Side ghetto was accidental, or whether it was done by the Mercenaries; but it is definitely settled now that the ghetto was fired by the Mercenaries under orders from their chiefs.
Wikipedia foundation.