Installation or installation art - Art that is or has been installed - arranged in a place - either by the artist or as specified by the artist. It might be either site-specific or not, and either indoors or out. The term became widely used in the 1970's and 1980's, and continues to be employed by many people. Installation may be temporary or permanent, but most will be known to posterity through documentation. As a consequence, one aspect of installation is often the difficulty with which they can be commodified.
-as is defined by artlex.com 1/9/2011