Suppose we are looking at Internet domain names. Every country has its own two-letter abbreviation (.fr, .uk, .ca, .za, etc.) — except for the US, as far as I know. They have .com, .org, .edu, .gov. I assume there's an historic reason for this, but what I'm wondering is: is there a term to describe the assumed centrality of the US in the domain-name world — the country being so "central" that it does not even need to be identified. Only the other needs to be identified.
Now suppose we are in Europe or North America. I'm asked to describe a man. "He's five foot eight, brown hair, wearing a beige suit..." I know in North America and I presume in Europe, that unless I specifically state otherwise, he is assumed by most of my listeners to be white. In other words, whiteness like the US, is assumed to be so central that it does not need to be identified.
I could give many more examples of the margin vs. the centre, but hopefully these two illustrate what I mean.
My Question: Is there a term that describes this centrality — the centrality of not needing to be labelled, if you will?
I don't know how to research the question either on this site or elsewhere.