Tarpaulin

A tarpaulin is a piece of strong, bendable and waterproof material. It is often made of a few types of plastics. They also often have fasteners to allow for ropes to be attached.
Cheaper modern tarpaulins are made from polyethylene; this material is so associated with tarpaulins that it has become colloquially known in some quarters as polytarp.
It is used to cover crime scenes, as a building material and to protect from weather such as rain.