CQ WW Puerto Rico

DX is not really considered by status as a "country" but status as a "DX Entity". Great examples: Hawaii and Alaska are both part of the United States but each is considered a separate DX Entity. There are only about 195 actual "countries" in the world but there are right now about 340 "DX Entities". It changes fairly often, as new islands become DX entities when a DXpedition visits them etc. The rules for determining what a DX entity are can be found at ARRL. They are the official determining "agency" of what qualifies as a DX Entity as its considered in ham radio.

List of "entities": http://www.arrl.org/files/file/DXCC/2019 DXCC Current.pdf

So you really do need the exact prefix of "all those little islands" to determine its status as a DX Entity or just part of another DX entity.

Dave
W7UUU