How do you spell Firing

Available Definitions:
1)  n. - The act of disharging firearms.
2)  n. - The mode of introducing fuel into the furnace and working it.
3)  n. - The application of fire, or of a cautery.
4)  n. - The process of partly vitrifying pottery by exposing it to intense heat in a kiln.
5)  n. - Fuel; firewood or coal.