User blog comment:XScar/Story Arc Names/@comment-48285-20121128002954

I believe that the reason why none of them are official canon is because Togashi doesn't name the storylines he does. They're just names given by people to differentiate between the different story focus. As for the "Yoknew City" and "Phantom Troupe" Arc names, I'd say they're pretty much interchangable. That, and I don't really think it matters what the arc is called, it's all Hunter X Hunter.