When fans of “Yacht Rock” aren’t killing time by deciding what songs qualify and don’t, there’s always a secondary question to ponder. What would you call it if not “Yacht Rock”? While the term’s creators have a relatively narrow definition, listeners and radio often use the term to define any soft pop from the mid-‘70s-through-early ‘80s. I sometimes hear that music referred to as “AM Gold,” after the compilation albums, but that’s not quite accurate for songs that were being heard on FM through headphones by 1981. Or Steely Dan’s “FM.”