An adjective meaning self-completing, from the Greek "auto" for "self" and "telos" for "end" or "purpose" (as in teleology).
The term comes from the New Critical school of literary criticism, which held that a work of literature (or art) should be considered to be a discrete object. Social, biographical, and other considerations may be interesting, but ultimately the meaning of a work can only be found in the work itself.
This school held that the "purpose" of art was to be beautiful, not to moralize or serve some outside purpose. Art for art's sake.
So, an autotelic work is one that is its own end. Autotelism is the belief that art is autotelic, or the state of being autotelic.