An autobiography recounts the author's entire life, usually from birth until the time of the writing. A memoir focuses on one aspect or period of the author's life.
For instance, if Hillary Rodman Clinton wrote a memoir, she might call it A Million Miles to refer to the 973,000 miles she traveled while she was Secretary of State. If she wrote her autobiography, she might call it Being My Own Person. This second, not-very-good title would be an examination of her entire life.
I know the difference between memoir and autobiography
and I use the terms correctly.