In architecture, post and lintel (also called prop and lintel or a trabeated system) is a building system where strong horizontal elements are held up by strong vertical elements with large spaces between them. This is usually used to hold up a roof, creating a largely open space beneath, for whatever use the building is designed. The horizontal elements are called by a variety of names including lintel, header, architrave or beam, and the supporting vertical elements may be called columns, , or . The use of wider elements at the top of the post, called capitals, to help spread the load, is common to many traditions.