I always thought the "pop" just meant "popular", esp. when you look at music in lots of stores, they have it labeled "Rock/Pop", and that's usually where the Journey stuff is!
I looked up "pop" music anyway just out of curiosity what it's labeled these days, funny stuff to find it has so many facets, I started reading them like Bubba in Forrest Gump when he's explaining all the different shrimp dishes

:
Avant-pop - Baroque pop - Bastard pop (

) - Bubblegum pop - Dance-pop - Girly-pop - Disco - Indie pop - Manufactured pop - Noise pop - Operatic pop - Power pop - Sophisti-pop - Space age pop - Sunshine pop - Synthpop - Teen pop
Fusion genres
Country pop - Dream pop - Electropop/Technopop- House-pop - Jangle pop (WTH is that?

) - Pop folk - Pop punk - Pop rap - Pop rock - Psychedelic pop - Urban pop