The Princeton Encyclopedia of Poetry and Poetics
Describes a work of art that imitates the style, gestures, or forms of an older work or antique model. As a formal descriptor of literary works, the word pastiche dates back centuries; as an evaluative term, its usage gradually acquired a hint of negative or dismissive connotation. The work implies a lack of originality or coherence, an imitative jumble. It was only in the latter half of the 20th c.---and most esp. in the context of theories of postmod. narrative---that patische acquired its current critical purchase.
Bowen, Claire. "Pastiche." In The Princeton Encyclopedia of Poetry and Poetics, 4th ed., edited by Stephen Cushman, Clare Cavanagh, Jahan Ramazani, and Paul Rouzer, 1005. Princeton [N.J.]: Princeton University Press, 2012.