post-impressionism (n.)

word-forming element meaning "after," from Latin post "behind, after, afterward," from *pos-ti (source also of Arcadian pos, Doric poti "toward, to, near, close by;" Old Church Slavonic po "behind, after," pozdu "late;" Lithuanian pas "at, by"), from PIE *apo- (source also of Greek apo "from," Latin ab "away from" see apo-).

1839 as a term in philosophy, from impression + -ism. With reference to the French art movement, 1879, from impressionist. Extended 1880s to music (Debussy), literature, etc.