Definitions for "Humidity, Relative"
The ratio of the pressure of water vapor present to the pressure of saturated water vapor at the same temperature.
is the ratio of the actual partial vapor pressure in an air-vapor mixture to the saturated vapor pressure at the existing dry-bulb temperature mixture.
Ratio of the amount of water vapor present in the air to that which the air would hold at saturation at the same temperature. It is usually considered on the basis of the weight of the vapor, but for accuracy it should be considered on the basis of vapor pressures.