Source : Webster's Revised Unabridged Dictionary (1913)

Post-impressionism \Post`-im*pres"sion*ism\, n. (Painting)
   In the broadest sense, the theory or practice of any of
   several groups of recent painters, 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 C['e]zanne, Matisse, etc.; but it is more
   broadly used to include cubism, the theory or practice of a
   movement in both painting and sculpture which lays stress
   upon volume as the important attribute of objects and
   attempts its expression by the use of geometrical figures or
   solids only; and futurism, a theory or practice which
   attempts to place the observer within the picture and to
   represent simultaneously a number of consecutive movements
   and impressions. In practice these theories and methods of
   the post-impressionists change with great rapidity and shade
   into one another, so that a picture may be both cubist and
   futurist in character. They tend to, and sometimes reach, a
   condition in which both representation and traditional
   decoration are entirely abolished and a work of art becomes a
   purely subjective expression in an arbitrary and personal
   language.