Humidity
There is no difference, a psychrometer is a type of hygrometer.
A measurement of how much water vapor is in the air at any particular place is called relative humidity. Relative humidity is measured with a psychrometer.
An antonym for a psychrometer could be a hygrometer, which measures relative humidity without the use of a wet bulb thermometer.
Like in a Hygrometer to measure humidity you use percentage (%)
A psychrometer is a simple form of hygrometer, an instrument which measures relative humidity. The psychrometer compares the dry-bulb and wet-bulb air temperatures.The "whirling psychrometer" is an instrument for the measurement of the temperature and humidity of the air. It contains two Mercury-in-glass thermometers with a scale of minus 5 to plus 50 degrees Celsius, in 0.5 degree increments. One is an ordinary dry bulb thermometer and the other wet bulb thermometer whose bulb is surrounded by a piece of thin muslin, kept moist with distilled water.
To use a psychrometer, follow these steps: Wet the wick or sling of the psychrometer with distilled water. Swing the psychrometer in the air for a few minutes to allow evaporation to take place. Read the dry-bulb and wet-bulb temperatures from the psychrometer. Use these readings to calculate the relative humidity using a psychrometric chart or formula.
The two parts of a psychrometer is the dry-bulb thermometer and the wet-bulb thermometer.
Humidity
The sling psychrometer was invented in 1887 by Adolph Richard Assmann, a German meteorologist. It is a simple instrument used to measure the relative humidity of the air.
Humidity
you buy a pychrometer
It measures the humidity.