Period and styles of painting, sculpture, graphic arts, and architecture dating from the late 19th century to the present date and characterized by a rejection of traditional artistic forms and conventions. It typically reflects changing social, economic, and intellectual conditions. Modern art includes numerous movements and theories. It differs from contemporary art, which does not carry the implication of a non-traditional style, but instead refers only to the time period in which the work was created. 'Modern' and 'contemporary' are inherently fluid terms. The term 'modern' sometimes more narrowly refers to art up until the 1960s or 1970s.

Source: Art & Architecture Thesaurus

http://vocab.getty.edu/page/aat/300264736