Strong's G4451 — πύρωσις (noun)
purosis (poo'-ro-sis) n.
1. ignition
2. (specially) smelting
3. (figuratively) conflagration, calamity as a test
[from G4448]
KJV: burning, trial 
Root(s): G4448 
Hebrew root: πυρόω
Occurrences: 3