What is Billie Holiday's nickname in The Autobiography of Malcolm X?
The answer to this question can be found on p. 113 of The Autobiography of Malcolm X. If you have an edition with different page numbers, you can find it a couple of pages into Chapter 7, which is entitled “Hustler.” Billie Holiday’s nickname was “Lady Day.”
Chapter 7 is a part of the section of the book where Malcolm X talks about his youth. At this point in the book, he is in his late teens and early 20s and he is wandering and aimless. He lives a life of petty crime, but one that gets him enough money to allow him to wear “the finest” suits (albeit stolen) and to have an active night life. During this time, Malcolm’s brother Reginald is in the Merchant Marine and, when his ship is in port, they go around to various nightspots. While they were doing this, they met important black musicians, one of whom was Billie Holiday. As Malcolm says on p. 113:
The great Lady Day, Billie Holiday, hugged him and called him “baby brother.”
From this, we can see that Billie Holiday’s nickname was “Lady Day.”