From AMS Glossary
Same as vapor pressure.
- The maximum possible vapor pressure that can be exerted, at a given temperature, by a system composed of a plane surface of a liquid or solid substance in contact with that substance's vapor.
As in the case of solutions, the vapor need not be of the same chemical composition as the parent substance. As so used, vapor tension is an intrinsic property of a substance, usually attributed to its liquid or solid state.
Compare equilibrium vapor pressure, saturation vapor pressure.