A waterproof sheet is a type of material that is designed to be impervious to water. It is often used in outdoor applications such as camping, boating, and construction. The two most common terms for this type of material are TARPAULIN (9 letters) and tarp (4 letters). TARPAULIN is a heavy-duty fabric made from polyester or canvas, while tarp is a lighter-weight plastic sheeting. Both materials are designed to be waterproof and provide protection from the elements.