| 1. | (Physics) The pressure or tension of a confined body of vapor of a chemical substance in equilibrium with the solid or liquid form of the substance. The pressure of a given saturated vapor is a function of the temperature only, and may be measured by introducing a small quantity of the substance into a barometer and noting the depression of the column of mercury. |
| Noun | 1. | vapor pressure - the pressure exerted by a vapor; often understood to mean saturated vapor pressure (the vapor pressure of a vapor in contact with its liquid form) Synonyms: vapour pressure |