flysheet

The term "flysheet" most commonly refers to the waterproof or water-resistant outer layer of a tent. It is set up over the main tent body, often called the inner tent, and gives important protection from rain, wind, and sun. A flysheet often extends beyond the inner tent a little, which can create a small covered area for boots, bags, or other gear.

Modern flysheets are usually made from light but strong synthetic materials such as nylon or polyester. These fabrics are often treated or coated to resist water. In practical use, the flysheet is one of the key parts that helps a tent stay dry and more comfortable in bad weather.

In some contexts, the word can also refer more loosely to a protective outer sheet or cover, but this is much less common. In everyday English, especially in camping contexts, a flysheet is the outer cover of a tent.