An Etymological Dictionary of Astronomy and Astrophysics

1. A style of painting developed in the last third of the 19th century, characterized chiefly by short brush strokes of bright colors in immediate juxtaposition to represent the effect of light on objects.
   

2. A manner of painting in which the forms, colors, or tones of an object are lightly and rapidly indicated.
   

3. A manner of sculpture in which volumes are partially modeled and surfaces roughened to reflect light unevenly (Dictionary.com).

See also: → impression; → -ism.