volatile

Etymology

From Middle French volatile, from Latin volātilis (“flying; swift; temporary; volatile”), from volō (“I fly”).

adj

1. (physics) Evaporating or vaporizing readily under normal conditions.
2. (of a substance, informal) Explosive.
3. (of a price etc) Variable or erratic.
4. (of a person) Quick to become angry or violent.
   a volatile man
5. Fickle.
6. Temporary or ephemeral.
7. (of a situation) Potentially violent.
8. (programming, of a variable etc.) Having its associated memory immediately updated with any changes in value.
   This method stores a value into a non-volatile field called result, then stores true in the volatile field finished. The main thread waits for the field finished to be set to true, then reads the field result. 2010, Jon Jagger, Nigel Perry, Peter Sestoft, Annotated C# Standard, page 467
9. (computing, of memory) Whose content is lost when the computer is powered down.
10. (obsolete) Passing through the air on wings, or by the buoyant force of the atmosphere; flying; having the power to fly.

noun

1. A chemical or compound that changes into a gas easily.
2. (programming) A variable that is volatile, i.e. has its associated memory immediately updated with any change in value.
   Operations on C++ volatiles do put the compiler on notice that the object may be modified asynchronously, and hence are generally safer to use than ordinary variable accesses. 2011, Victor Pankratius, Ali-Reza Adl-Tabatabai, Walter Tichy, Fundamentals of Multicore Software Development, page 74