AR meaning in Governmental ?

Seaman recruit (SR) is the lowest enlisted rate in the United States Navy, U.S. Coast Guard, and the U.S. Naval Sea Cadet Corps just below seaman apprentice; this rank was formerly known as seaman third class. Two separate pay grades exist within this rank (and the corresponding ranks in the other branches of the United States military structure) — one for those with service of less than four months, with a higher pay scale for those in service for more than four months, even if they have not yet advanced to seaman apprentice.