Alan Freed in History of Rock & Roll
Alan Freed (1921–1965) was a charismatic 1950s disc jockey known as "Moondog" who organized large concerts featuring African-American rhythm & blues artists. He's thought by some to have coined the term "rock and roll," a phrase he used in marketing his events to concertgoers.
In May 1952, DJ Alan "Moondog" Freed organized a concert at the Cleveland Arena in Ohio, which featured artists such as the Dominoes and Paul "Hucklebuck" Williams, and attracted nearly 25,000 young concertgoers, mostly African Americans.
In the following years, Freed continued throwing events featuring popular rhythm & blues artists, and billed his shows as "Rock 'N' Roll" parties, perhaps single-handedly popularizing the term.