structure in which weight is carried by a skeleton or framework, as opposed to being supported by walls. The essential factor in a framed building is the frame's strength. Timber-framed or half-timbered houses were common in medieval Europe. In this type the frame is filled in with wattle and daub or brick. A modern lightweight wood-frame structure, the balloon-frame house with wood cladding, was invented in Chicago and helped make possible the rapid settlement of the western United States. The framed building enjoyed an extensive revival after World War II as the basic form of American suburban housing.

Steel and reinforced concrete are the most common materials in large contemporary structures. During the 19th century, brick or stone walls continued to bear loads, though cast-iron framing was sometimes used supplementarily, being embedded in walls or sometimes freestanding. True skeletal construction on a large scale was first achieved in Chicago by William Le Baron Jenney (Jenney, William Le Baron) in the Home Insurance Company Building (1884–85). This building featured a frame of both iron and steel. In the 20th century reinforced concrete emerged as steel's main competitor.

The French architect Auguste Perret (Perret, Auguste) was the first to give external expression to a framed building (1903); he exposed as much as possible the reinforced-concrete framework of his buildings and eliminated most nonstructural elements. Contemporary architecture has done away with most traditional walls altogether by the use of metal and glass screens, or curtain walls, as exterior cladding.