An Artist Run Centre is an art institution that lacks many of the traits of a commercial gallery space.
By methods and ideologies made popular (particularly in North America) in the late 1970s, artist run culture came to prominence in response for the need of an alternative to conventional gallery spaces.
Generally working within an established framework, the artist run centre is now charged with understanding and challenging ongoing contemporary discourse. There aren't typically established limits (save, perhaps the cost) of what can be shown visually. The artist run centre often looks outside of its own limitations and boundaries to maintain an active status in its own community.
Artist run centres also generally operate/rely on government grants, as opposed the sale of art to maintain their spaces and programs. This assists in eliminating the need to make art specifically for sale, thus giving the participating artist the freedom to create pieces that, if they so choose, distinctly lack commercial ends (i.e. performance art, music, experimental pieces, etc.).
As a result, these institutions (generally found in urban centers) become not only culturally relevant, but employ distinct voices within their respective communities. Artist run centres generally have a board of directors and/or staff that are practicing artists or curators themselves (hence the moniker).