📍 : The term "Pop" is short for "Popular." If a song becomes widely loved enough, regardless of its original style, it effectively joins the pop index. If you'd like, I can: Provide a playlist of essential pop hits by decade. Break down the best-selling pop albums of all time. Help you write a pop song using a standard structure.
For those seeking a "serious" index, publications like Rolling Stone, Pitchfork, and the Rock & Roll Hall of Fame offer definitive lists.
The visual index became as important as the audio. The Roland TR-808 drum machine defined the index.
Musicmap : An interactive genealogy mapping the relationship between pop subgenres like disco, punk, and synth-wave. The Evolution of the Pop Index