Abstract Art, art that uses forms having no direct reference to external or perceived reality; it is usually synonymous with various types of 20th-century avant-garde art. The term abstract also refers to images that have been abstracted or derived from nature, but which in the process have been considerably altered or have been simplified to their basic geometric or biomorphic forms. The term nonobjective, once used to describe certain kinds of abstract art, has been abandoned by most contemporary art critics and historians. See Abstract Expressionism; American Art; Bauhaus; Canadian Art; Collage; Constructivism; Cubism; Dada; Futurism; Modern Art; Painting; Prints and Printmaking; Sculpture.