What does r r stand for?

It could mean: * Reference range, in laboratory medicine. * Relative risk, in statistics and epidemiology * Respiratory rate, as a vital sign * Rhesus factor, in immunohematology. * Chip 'n Dale Rescue Rangers, an animated TV series * Rainbow Road, a course in the Mario Kart series * Reading Rainbow, an American children's television program * Rickrolling, an internet meme * Ricky Ricotta, a children's book series by Dav Pilkey * Road Rules, a reality series on MTV * Rocka Rolla, heavy metal album by Judas Priest * Royal Rumble, annual WWE pay-per-view * Rockin' Robin * Rachael Ray, an American television personality * Ronald Reagan, 40th President of the United States of America * Robert Reiner, actor * Rick Robertson, AKA Double R, Seattle radio personality * Rajasthan Royals, an Indian Premier League franchise * Rashtriya Rifles, Indian counter-insurgency force * Reach Records, a Christian hip hop record label * Red Rooster, an Australian fast food chain * Rekords Rekords, an American record label founded by Josh Homme * Road Runner (ISP) * Royal Air Force, IATA airline designator * Rational Recovery * RR layout, Rear-engine, rear-wheel drive layout, in automotive terminology * Request-response, a synchronous messaging model commonly used in distributed computer systems * Resource records used in Domain Name System (DNS). * Riva Rocci, an abbreviation for blood pressure measured with a specific sphygmomanometer * Round-robin scheduling * Railroad * Rapid Ride, a bus rapid transit system in Albuquerque, New Mexico * Regional Railways, a former sector of British Rail * Regional Roads in Ontario, a class of roads maintained by regional municipalities in Ontario (see County roads in Ontario) * Royal Road, an ancient highway reorganized and rebuilt by the Persian king Darius I * rr (digraph) * Reader Rabbit * Repurchase agreement rate (or repo rate; as in the Reuters Instrument Code US10YT=RR) * Revised Romanization of Korean * Rio Rancho, New Mexico * Rolls-Royce (disambiguation) * Roman Republic * Rural route * Russian ruble If you meant R & R, it probably means either "rest and rehabilitation" (military sense) or "rest and recreation".