Biography: "A biography is a written account of a person's life. It is a narrative, written by someone other than the subject of the book, which includes details about upbringing, schools attended, family and home life, career accomplishments, struggles, and other achievements and failures. It often includes intimate details about the person's life and is usually in the nonfiction genre" (Owen, 2020).
Autobiography: "An autobiography is a book about a person written by that person. The word comes from the Greek words autos (self), bios (life), and graphein (to write). An autobiography often begins with the birth of the author, or the author’s parents, and then follows the time line of the author’s life. Facts, research, and interviews, along with letters, certificates of birth, and school or employment records, may be used by the author." (Castaneda, 2019, Autobiography).
Memoir: "A memoir is a personal account of one’s past experiences. Although memoir overlaps with autobiography, the main focus of a memoir may be on the writer’s experiences with noteworthy people, events, or places rather than on his or her own life. The word “memoir” derives from the French word mémoire and the Latin term memoria, meaning “memory” (Castaneda, 2019, Memoir).
References
Castaneda, K. M. (2019). Autobiography. Salem Press Encyclopedia of Literature.
Castaneda, K. M. (2019). Memoir. Salem Press Encyclopedia of Literature.
Owen, M.-J (2020). Biography. Salem Press Encyclopedia of Literature.