Interdisciplinary is an adjective meaning relating to more than one branch of knowledge. So, interdisciplinary art is literally art that consists of more than one form of art.
There are many conventional/traditional art genres, like creative writing, performance art, music, theatre, and visual arts. Through interdisciplinary arts, two or more of those genres are amalgamated together into the direction and final product.
Although the term of interdisciplinary art is rarely found in art history, there are many artists that have been exploring it. William Blake for example, the classic poet-printmaker-mystic is considered as an interdisciplinary artist. His work, “The Marriage of Heaven and Hell” is a testament to his interdisciplinary art. In the modern era, video artist Bill Viola, musician-poet-film maker-graphic artist Yoko Ono, and composer-choreographer-director Meredith Monk are the best example of interdisciplinary artists.
Interdisciplinary art is about freedom of expression and honing multiple skills and talent. It is a way to build a bridge between different forms of art, and for any artist who desires to investigate and integrate different modes of creative expression.
The methodology of interdisciplinary arts often relies on collaboration. Outcomes of such collaborative processes can be performance art, durational performance art (live art), or video art.