lu·mi·nism also Lu·mi·nism 
(lmə-nĭz′əm)
(lmə-nĭz′əm)n.
A style of 19th-century American landscape painting concerned especially with the meticulous rendering of atmospheric light and the perceived effects of that light on depicted objects.
[Latin lūmen, lūmin-, light; see LUMEN + -ISM.]
lumi·nist adj. & n.