Meaning of volatile

vol•a•tile

1. evaporating rapidly; passing off readily in the form of vapor: Acetone is a volatile solvent.
2. tending or threatening to break out into open violence; explosive: a volatile political situation.
3. changeable; mercurial; flighty: a volatile disposition.
4. (of prices, values, etc.) tending to fluctuate sharply and regularly: volatile market conditions.
5. fleeting; transient: volatile beauty.
6. of or pertaining to storage that does not retain data when electrical power is turned off or fails.
7. able to fly or flying.

1. a volatile substance, as a gas or solvent.