[jkqwzsoo]

I couldn't find anything either.

My guess would be that you aren't technically in the PhD program until you've passed your qualifying exam. Until that point, you're a graduate student but not a PhD student. After you pass your preliminary exam, you're a PhD/Doctoral candidate.

Also, it's a moot point. There are no bragging rights to be found in simply being admitted to a PhD program. Plenty of very intelligent people fail to complete a PhD program (usually, IME, because of personality issues/conflict with the advisor (sadly extremely common), inflexibility of the advisor and/or department, or personal reasons (economic, social, health)).

(to be clear, Musk didn't brag that he was admitted to Stanford - he suggested that he felt dropping out was more useful than continuing. His fans often hold up being admitted to a PhD program as evidence of his engineering background)

[chriskanan]

In the USA, this is how it typically works. People who are enrolled in PhD programs are called "PhD students." Once they pass their advancement to candidacy exam, they are called "PhD Candidates." In both cases, they are enrolled in a PhD program. Typically people are accepted directly to PhD programs and they are not just admitted as generic graduate students.