The process of evaporation in a closed container will proceed until there are as many molecules returning to the liquid as there are escaping. At this point the vapor is said to be saturated, and the pressure of that vapor (usually expressed in mmHg) is called the saturated vapor pressure.

What does it mean when a vapor is saturated?

: vapor at the temperature of the boiling point corresponding to its pressure and so incapable of being compressed or cooled without condensing — compare equilibrium sense 1c.

How do you know if a vape is liquid or saturated?

A liquid that is about to vaporize is called a saturated liquid. Once boiling starts, the temperature stops rising until the liquid is completely vaporized. Any heat loss from this vapor will cause some of the vapor to condense. A vapor that is about to condense is called a saturated vapor.