reminiscence

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of recollecting past experiences or events.
• noun An experience or event recollected.
• noun A narration of past experiences.
• noun An event that brings to mind a similar, former event.

from The Century Dictionary.

• noun In biology, the retention by a modern organism, during its development, of traces of the effect of past ancestral history.
• noun The act or power of recollecting; recollection; the voluntary exertion of the reproductive faculty of the understanding; the recalling of the past to mind.
• noun That which is recollected or recalled to mind; a relation of what is recollected; a narration of past incidents, events, and characteristics within one's personal knowledge; as, the reminiscences of a quinquagenarian.
• noun In music, a composition which is not intended to be original in its fundamental idea, but only in its manner of treatment.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act or power of recalling past experience; the state of being reminiscent; remembrance; memory.
• noun That which is remembered, or recalled to mind; a statement or narration of remembered experience; a recollection.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An act of remembering long-past experiences, often fondly.
• noun A mental image thus remembered.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a mental impression retained and recalled from the past
• noun the process of remembering (especially the process of recovering information by mental effort)