Here’s a question: why do we call it “pop” music?
A little research suggests that the world was first used in 1949 in an article in a defunct British music paper called Melody Maker. It was deep in a gossip column item on big band leader Benny Goodman, which referred to him as a “consulting director of pop music” on (for whatever reason Russian language radio programs.)
The word really caught in 1953 and 1954 when 7-inch 45 rpm records really started to take hold in the marketplace. Albums were for adults; singles were for kids. By this time, there were several charts keeping track of the best-selling singles. These charts kept track of “popular” music–or “pop music” for short.