Post-impressionism is a great name for an art movement – even if none of the artists involved has ever heard of it! The term was actually invented years later by a pair of British critics.
The writer, editor, and museum director Roger Fry shows at London’s Grafton Galleries of works by modern French masters, notably Cezanne, Gauguin, and Matisse, with a few Cubists thrown in for good measure. The English aesthetician and critic Clive Bell (1881-1964) also used the name in his book of essays, Art (1914).
Thus history was made, a couple decades late.
So Postimpressionism, not to put too fine a point on it, is a catch-all term that describes art that came after Impressionism. From the 1880s to the end of the century, Postimpressionist artists kept Impressionism’s bright colors but added a whole new focus on meaning, whether primitive, mystical, or scientific.