n.
Pronunciation: ' v ā -p ə r
Function: noun
Etymology: Middle English vapour, from Anglo-French vapor, from Latin, steam, vapor
Date: 14th century
1 : diffused matter (as smoke or fog) suspended floating in the air and impairing its transparency
2 a : a substance in the gaseous state as distinguished from the liquid or solid state b : a substance (as gasoline, alcohol, mercury, or benzoin) vaporized for industrial, therapeutic, or military uses also : a mixture (as the explosive mixture in an internal combustion engine) of such a vapor with air
3 a : something unsubstantial or transitory : PHANTASM b : a foolish or fanciful idea
4 plural a archaic : exhalations of bodily organs (as the stomach) held to affect the physical or mental condition b : a depressed or hysterical nervous condition