'flashback' definitions:

Definition of 'flashback'

From: WordNet
noun
A transition (in literary or theatrical works or films) to an earlier event or scene that interrupts the normal chronological development of the story [ant: flash- forward]
noun
An unexpected but vivid recurrence of a past experience (especially a recurrence of the effects of an hallucinogenic drug taken much earlier)

Definition of 'flashback'

From: GCIDE
  • flashback \flashback\ n.
  • 1. a transition (in literary or theatrical works or films) to an earlier event or scene; also, the scene thus introduced. [WordNet 1.5]
  • 2. An unusually vivid recollection of a prior experience, often one that is traumatic, such as scenes from combat or a criminal assault, or induced by hallucinogenic drugs such as LSD; when accompanied by hallucinations it is called flashback hallucinosis. [PJC]

Synonyms of 'flashback'

From: Moby Thesaurus