What is meant by the term absolute humidity?

Absolute humidity refers to the actual amount of water vapor present in a given volume of air, typically expressed in grams of water vapor per cubic meter of air. It provides a direct measure of the mass of water vapor, regardless of temperature or pressure conditions. This measurement is important in various fields, including meteorology and aviation, as it helps in understanding humidity's impact on air density and overall atmospheric phenomena.

The other definitions describe concepts related to humidity but do not accurately define absolute humidity. For instance, total weight of water vapor in the air could refer to various volumes and is not a standardized measurement. Maximum amount of water vapor refers to the concept of saturation humidity, indicating limits rather than actual current conditions. The percentage of water vapor describes relative humidity, which compares the current amount of water vapor to the maximum possible at a specific temperature. Thus, absolute humidity distinctly focuses on the real quantity of water vapor in the air.