It is a very simplified looking cloud. It is composed of the intersection of three circles and a rectangle, forming a shape not unlike a lumpy cumulus cloud.
This Clouds icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,700 icons, all in the same style and quality.