General:
* Passage
* Extract
* Selection
* Quote
* Snippet
* Fragment
* Portion
* Bit
* Piece
More specific:
* Clipping (from a newspaper or magazine)
* Cut (from a film or recording)
* Sample (from a larger work)
* Epitome (a concise and representative part of a larger work)
* Abridgment (a shortened version of a longer work)
Less formal:
* Chunk
* Part
* Section
* Paragraph
The best synonym to use will depend on the specific context and the tone you want to convey.