Plain English Meaning

The microscopic water drops that make up a cloud. They are small enough to float in the air, and when they are colder than freezing they can freeze onto an aircraft when it flies through them.

Full Definition

Tiny liquid water particles suspended in the air that together form a visible cloud. Individual droplets are very small (typically a few to a few tens of microns across) and remain airborne because their size keeps them aloft on rising air. In below-freezing temperatures, cloud droplets can exist as supercooled liquid water that freezes on contact with an aircraft, producing structural icing.

Context Anchor

Seen in icing discussions, especially when explaining why an aircraft can pick up ice while flying through a visible cloud.