In the USA ( vs. Austria) 16:59 Sep 11, 2011
one is an "intern" first ( 1 year), then becomes a "resident" in a specialty (often abbreviated as PGY-1, PGY-2...(post-graduate year 1, 2). At the end, one can become a "chief resident". "Registrar", however, is not used in the USA and would not be understood. A registrar in the USA is a college/university official dealing with transcripts and other academic administrative matters....
In Austria, one is first "Turnusarzt" ( 3 years, ending with jus practicandi)and then goes on ( or not) to become an Assistenzarzt in a specialty. Once that training period is competed, one is promoted to OA (Oberarzt; senior physician). | 
The translation workplace 
peer agreement (net): +2
