A wildfire, also known as a wildland fire, forest fire, brush fire, vegetation fire, grass fire, peat fire, bushfire (in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources. Common causes include lightning, human carelessness, arson, volcano eruption, and pyroclastic cloud from active volcano. Heat waves, droughts, and cyclical climate changes such as El Niño can also have a dramatic effect on the risk of wildfires.
The word "wildfire" was once a synonym for Greek fire as well as a word for any furious or destructive conflagration. According to the Oxford English Dictionary, the earliest known usages are specifically for lightning-caused conflagrations. The modern usage may have arisen in part from people misunderstanding the expression "spread like wildfire".
