A patio door is a type of door designed to provide access to outdoor spaces, such as patios or decks. Typically made of glass, these doors allow natural light to enter a home while offering a view of the outside. They can come in various styles, including sliding, hinged, or bi-fold designs, catering to different aesthetic preferences and space requirements. Patio doors are often equipped with features like screens to keep insects out and locks for security. They are commonly made from materials such as wood, vinyl, or aluminum, ensuring durability and energy efficiency. Proper installation and maintenance can enhance their functionality and lifespan.