How about [this][1] from Merriam Webster

>## Mise en abyme ##
>
> - placement at the center of an escutcheon of a smaller copy of the same escutcheon
> - containment of an entity within another identical entity 
> - image of an image


And from [Wikipedia][2], how mise en abyme is used in film:

> Mise-en-abîme occurs within a text when there is a reduplication of images or concepts referring to the textual whole.[...] In film, the meaning of "mise en abyme" is similar to the artistic definition, but also includes the idea of a "dream within a dream". For example, a character awakens from a dream and later discovers that s/he is still dreaming. 

The article on Wikipedia specifically mentions Inception as an example of this. 



  [1]: http://www.merriam-webster.com/dictionary/mise%20en%20abyme
  [2]: http://en.wikipedia.org/wiki/Mise_en_abyme