A window is an opening in a wall or structure that is typically filled with glass. It allows light to enter a space while providing a view of the outside. Windows can be opened or closed to control airflow and temperature, and they come in various shapes and sizes, such as rectangular, circular, or arched. Windows are often framed with materials like wood, vinyl, or aluminum. They can be single-pane or double-pane, with double-pane windows offering better insulation. In addition to their practical uses, windows also contribute to the aesthetic appeal of buildings and homes, enhancing their overall design.