From Longman Dictionary of Contemporary Englishwater vapourˈwater ˌvapour British English, water vapor American English noun [uncountable] HCwater in the form of small drops in the air
Examples from the Corpus
water vapour• Water vapour is a naturally occurring greenhouse gas but the amount of water vapour in the atmosphere is affected by human activities.• The platinum catalyses the reaction of carbon monoxide and hydrocarbons with air to give carbon dioxide and water vapour.• But water vapour is also a greenhouse gas.• Or will more water vapour feed the warming process?• The amount of water vapour in a battery depends on the concentration of sulphuric acid in the solution.• It must also provide a high level of water vapour resistance.• Incidentally, cavity wall insulation should be impermeable to water vapour, or interstitial condensation can occur.• Both ordinary and thermal plasterboard are also available with a backing film which makes it resistant to water vapour. 