Volatile means liable to change fast and without warning, usually for the worse. A volatile situation, a volatile market, a volatile temper — in every case the point is that you cannot rely on the next hour looking like this one.
It began as a chemistry word and still is one: a volatile liquid evaporates readily at ordinary temperatures, which is why petrol is volatile and water is not. That physical sense is the picture behind the human one, and it is a good picture to hold on to — volatile people and volatile markets both go off suddenly and leave nothing behind. Computing has a third sense with the same logic: volatile memory is memory that loses everything the moment the power goes.
1adjectivevolatileLikely to change suddenly and unpredictably.
“The situation on the border remains volatile.”
synonyms: unstable, unpredictable
2adjectivequickOf a person, quick to become angry or upset.
“He is brilliant and volatile, and the two are not unconnected.”
3adjectiveliquidOf a liquid, evaporating easily at ordinary temperatures.
“Store volatile solvents away from heat.”
4adjectivecomputerOf computer memory, losing its contents when the power is cut.
“Anything held in volatile memory is gone when the machine restarts.”
volatile is a quality of instability.
Latin volatilis meant flying — from volare, to fly, the same root as volley. A volatile substance is one that flies off; a volatile temper is one that flies up. The word never stopped being about something leaving the ground quickly.
Latin
volātilis — flying; swift; temporary; volatile
Middle French
volatile
English, today
volatile
Built from
From Middle French volatile, from Latin volātilis (“flying; swift; temporary; volatile”), from volō (“to fly”).
Etymology from Wiktionary, CC BY-SA