The most succinct definition of “pop” and “R&B” I’ve ever read:
The separate designation of pop and R&B bears explaining. Pop in the record industry is a euphemism for white; R&B means black. Until 1949 Billboard listed music by black artists as “race” records, but then a staffer named Jerry Wexler coined the term rhythm and blues. This is about all that has changed (though the industry has found other euphemisms, including “soul” and “urban”). A rock record by a black artist is automatically R&B – regardless of its sound – unless white people buy it, at which point it is said to “cross over” to the pop charts. Since white record buyers outnumber blacks by a large margin, a crossover hit means a bigger payoff.
Hit Men: Power Brokers and Fast Money Inside the Music Business