Definition from Wiktionary, the free dictionary
memoir (plural memoirs)
- An autobiography; a book describing the personal experiences of an author.
- When I retire, I'm going to write my memoirs.
- Any form of narrative describing the personal experiences of a writer.
Usage notes 
- A memoir differs from a simple autobiography by not focusing on the author as the primary subject matter, but on people and events in the author's life. Emphasis is placed on personal observations about external events.
- The plural memoirs is very often used to refer to a single work.
Related terms 
book describing the personal experiences of an author
any form of narrative describing the personal experiences of a writer
- memoir in The Century Dictionary, The Century Co., New York, 1911