In meteorological terms, what does humidity refer to?

Humidity in meteorological terms specifically refers to the amount of moisture present in the air. This is typically quantified as a percentage representing the current water vapor in the air relative to the maximum amount the air can hold at a particular temperature. Understanding humidity is crucial for analyzing weather patterns, predicting precipitation, and assessing comfort levels for humans since higher humidity levels can lead to a feeling of mugginess and are associated with higher chances of rain.

In contrast, the other options relate to different aspects of atmospheric conditions. Wind speed measures how quickly air moves through the atmosphere, air temperature indicates how hot or cold the air is, and atmospheric density describes how compact the air is at a given pressure and temperature. While these factors are all interrelated and contribute to the overall weather system, they do not define humidity.