Refers to the European movement affecting visual arts, literature, music, and to a lesser degree architecture from the mid-18th to the mid-19th centuries. Viewed as a reaction to Neoclassical formality, it stressed emotion and the right to individual expression. Works encompass a range of styles but in general are painterly, dynamic, and reflect an interest in color over line.

Source: Art & Architecture Thesaurus 

http://vocab.getty.edu/page/aat/300172863