The temperature of the air when it is cooled to saturation. (When saturation is reached, the air cannot hold any additional moisture, and any excess moisture condenses as dew on surface features such as grass or plants).
The temperature at which moist air becomes saturated (100% relative humidity) with water vapor when cooled at constant pressure.
The temperature to which air must be cooled for condensation to begin, assuming there is no air pressure or moisture content change. At that temperature dew begins to form, and water vapor condenses into liquid. Dew point temperature is a measure of the amount of water vapor in air.
the temperature to which air must be cooled to reach saturation
The temperature to which a given parcel of air must be cooled at constant pressure and constant water-vapor content in order for saturation to occur. In this handbook, the dew point temperature is defined with respect to liquid water.
The temperature at which water vapor turns to liquid in cooling air at the existing atmospheric pressure and vapor content.
the temperature at which water vapor condenses in cooling air at the existing atmospheric pressure and vapor content. Cooling at or below the dew point will cause condensation.
The temperature at which a body of air becomes saturated, holding all the water it can hold. Any further cooling or addition of water vapour results in condensation. In the atmosphere, this condensation results in cloud or fog formation.