A lean-to roof, also called a shed roof or sloping roof, is a single-sloping roof attached to a wall or building. The most common synonyms for lean-to roof are canopy, awning, shelter, and pergola. A canopy is an outdoor structure with a roof, typically made of cloth or metal, used for shade or shelter. An awning is a roof-like cover extending over an entrance or window to provide protection from rain or sun. A shelter is a simple structure with a roof, often made of natural materials like leaves or branches, used for protection from the elements. A pergola is an outdoor structure with a roof of beams or lattice that provides partial shade.