n. (Painting) In the broadest sense, the theory or practice of any of several groups of painters of the early 1900's, or of these groups taken collectively, whose work and theories have in common a tendency to reaction against the scientific and naturalistic character of impressionism and neo-impressionism. In a strict sense the term post-impressionism is used to denote the effort at self-expression, rather than representation, shown in the work of Cézanne, Matisse, etc.; but it is more broadly used to include