During his lifetime, Ellas Otha Bates’s name would undergo several changes. Born to Ethel Wilson in McComb, Mississippi, he would be raised by Ethel’s cousin, Gussie McDaniel and her husband, Robert McDaniel. Although he was never formally adopted by “Mama Gussie,” his name would change to Ellas Bates McDaniel for fear that he would not be able to enroll in school. The origins of McDaniel’s stage name, however, are the subject of extensive debate.
A diddley bow, thought to have its roots from the monochord zithers of Afrika, is the name of a single string instrument in the American Deep South made by nailing a length of broom wire to a plank, using a rock or bottle to form a movable bridge. It is played in the style of a bottleneck guitar with various objects used as a slider. Diddley played his famous song “Bo Diddley” in the same one string fashion on the guitar in the same style of the instrument. Colloquially, the term "diddley" comes from "diddley-squat" meaning worthless.
According to the National Blues Museum, the name was common among Black vaudeville performers along with names similar to it, for its “colorful interpretation and thought-provoking appeal.” Harmonicist Billy Boy Arnold said that it was a local comedian’s name which Leonard Chess adopted as McDaniel’s stage name and title of his first single.
If you asked the man himself, he would say neighborhood kids would tease him. As the teasing became more intense, McDaniels learned boxing. One day while fighting, one girl yelled out, “Man, you’re a bo diddley!” From then on, the name would stick with him throughout his life and career.