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 ]