The term avant-garde continues to be used, in my opinion with far too much frequency, in discussions of contemporary art. It derives, of course, from military terminology, and implies that the art to which it is applied is somehow ahead of the game.
It’s worth taking a look at how this assumption works in practice. Essentially, Western and now world art has witnessed the emergence of a series of avant-gardes since just before the third quarter of the 19th century. One may perhaps give Impressionism the honor of being the first avant-garde as we now understand matters. Until quite recently, avant-gardes tended to develop in orderly, quasi-hierarchical succession. Impressionism begat Post-Impressionism. Cubism was displaced in due course by Surrealism. Surrealism was displaced by Abstract Expressionism. Abstract Expressionism was vanquished by Pop Art, and Pop, in very short order, was challenged by Minimalism.