VAPOUR

UK and ANZ, [US and ANZ] vapor [noun] - gas which results from the heating of a liquid or solidThe hollow glass tank contains hot mercury vapour. [U]Poisonous vapours burst out of the factory during the accident. [C]Warmer air is able to hold more water vapour than cold air and so has a higher humidity. [U]The biggest greenhouse gas by far is water vapour. [U]A vapour trail is water vapour that looks like a line of white smoke behind an aircraft as it flies.High in the sky, we could see the vapour trails of the bombers moving northwards.