What is the difference between avant-garde and postmodern?

Avant-garde is generally used to refer to the avant-garde styles of the art world at various points in time. Avant-garde is a vague umbrella term for these styles, denoting their ***identical characteristics: radical and anti-conformist, and generally non-commercial. Similarly, within the theater arts, avant-garde does not denote a specific art style or genre, but is a generic term for all radical, anti-naturalistic, non-traditional and experimental theater styles.

Postmodernism, generally known as post-modernism, is originally a sociological concept. In the context of theater arts, it mainly refers to theatrical styles influenced by post-structuralism and deconstructionism. For example, there is no ending or an open ending, different situations are set up in one scene, and the final drama is to raise questions rather than to answer them, and so on.

Both are very vague concepts that are difficult to define. They overlap in some ways, and if there is a distinction to be made, it can only be that the avant-garde has no time limit, whereas the postmodernists are confined to the boundaries of the "time" of "postmodernity" (a concept whose definition itself is also subject to dispute).