What term describes the presence of very small drops of water in the air?

The term that describes the presence of very small drops of water in the air is humidity. Humidity specifically refers to the concentration of water vapor present in the atmosphere, which can cause various weather phenomena. When the air contains sufficient water vapor, it can lead to the formation of clouds, fog, and precipitation.

While other options like "humidity level" also relate to the amount of moisture in the air, they don't succinctly define the concept itself. "Moisture" is a broader term that can apply to water in various forms and contexts and does not specifically capture the atmospheric aspect in the same way. "Fog" refers to a weather condition resulting from high humidity when water vapor condenses into many tiny water droplets in the air, but it is a specific manifestation rather than a general term for the presence of water vapor itself. Thus, humidity is the most precise term related to tiny drops of water in the air.