I don't think that "whole world" coins would ever be used, since it sounds redundant to insert the adjective "whole". I like how Krause's Standard Catalog of World Coins includes the US. Whereas, sites like eBay seem to use "world coins" to refer to other countries' coins, possibly emulating what the major authorities for coins use (specifically of those authorities whose products appear on eBay, since consistency of terms may be better for sales; e.g. NGC and PCGS). I agree for the most part that the term "world coins" gets used liberally, and a more specific term can be used to describe one's collection. "World coins" has taken on another meaning among collectors - "non-domestic coins". That said, I can see "world coins" to mean what it is literally at face value. Similarly and for instance, I generally collect silver "world coins" (with other criteria and some exceptions). This means coins from all over the world including the US where I am from, which are composed of silver beyond mere silver plating (again, with some exceptions such as the 1923 Westphalia 1 billion Mark coin that's on my wish list). But yes, I agree with you that we don't necessarily know what a "world coin" collector means without elaboration or confirmation that they literally collect coins from all over the world, domestic and foreign.