Works that use non-art elements, often junk and/or debris, to form a work of art. Assemblages are sculptural works created since about 1945 by the technique of assemblage, the creation of a three-dimensional work of art by combining various elements, especially found objects. They may include elements painted, carved, or modeled by the artist. For such works created earlier in the 20th century, see "object sculpture."

Source: AAT

http://vocab.getty.edu/page/aat/300047194