Used in a broad sense, avant-garde refers to any trailblazing movement — usually artistic or social — led by a small group of people to open new doors within their realm of interest. Specifically, the term refers to a moment within the art world which encompasses many schools and sub-movements.
While avant-garde originally was used to describe only cutting-edge movements, as time has progressed many movements have retained the label long after they have ceased to be novel or groundbreaking. Dadaism and modernism, for example, are both considered examples of avant-garde art — though both have been around for nearly a century. This has led many to label movements as historically avant-garde, stressing that in a contemporary setting they are no longer cutting-edge forms of expression.
The term experimental is often used interchangeably with avant-garde, particularly when focusing on a specific area of artistic interest. Examples include experimental theatre and experimental film.
Attempts to specifically define and delineate what is and what is not avant-garde are necessarily problematic, since the definition is ultimately one of personal opinion. What seems cutting-edge and revolutionary to one group of critics may seem tame and overdone to another. While avant-garde schools such as Pop art and Fluxus have a fairly defined set of criteria for what makes a body of work belong to their school, the word itself has no such dictates. Rather, a piece is considered avant-garde if it is avant-garde — a circular reasoning that causes a great deal of general confusion.
Some efforts have been made recently to define the term more rigidly; these attempts set the criteria for an avant-garde piece to be primarily concerned with pushing the envelope with regards to the artistic experience. Works that exist primarily to make a political or social statement not focused on art, are not to be considered avant-garde.
A number of artists who are considered avant-garde have rejected the label entirely, most claiming it is more trouble than it is worth. It is perhaps ironic that the artists most likely to be given this name are those most opposed to confining labels — they desire to break free of boundaries and labels in their artistic expression.
Avant-garde is also sometimes used pejoratively, particularly when regarding a non-artistic sphere. Philosophical and scientific ideas, for example, may be dismissed as being avant-garde, indicating that they exist more as a token gesture to challenge standing theories and tradition than to present new substantiated ideas.