R and R is a term first used by the military to stand for "rest and recuperation," although it is often mistranslated as "rest and relaxation" or "rest and recreation." The acronym is in such common usage that it can really be used to refer to any of these phrases. However, a soldier would likely use it in the original, formal sense.
The military translation of R and R does not mean that soldiers may do much rehabilitating on a typical leave. Most soldiers benefit from the mixing with civilians and taking a break from the tense conditions that serving in the armed forces sometimes engenders, however.
For some in the military, R and R may cause problems. For example, sailors often have a very difficult time adjusting to life onshore because of their cramped and confined living conditions while at sea. The time away can actually provide no rest because service members may go through a few days adjustment to the wide-open freedom allowed by being on land.
For those not in the military, R and R is often used to refer to taking a vacation or participating in something fun. For example, a worker takes a few days of to play golf, and says to his buddies, “I’ve got three days of R and R coming up.”
R and R doesn’t always provide the needed break from the working environment. A single working mother who uses her time off to clean her house, take care of her kids, and do all the shopping, is not usually relaxing from the time she receives. Her family may benefit, but essentially the mom is still working.
There are many other terms that this acronym can stand for, including Rock and Roll, Read and Review, Remove and Replace, Repair and Return, and Rules and Regulations. In prison terminology, R and R stands for the Receiving and Release of prisoners. In the business world, the acronym is used by human resource departments to refer to Recruitment and Retention.
Organizations that help during natural disasters may use R and R for Response and Recovery. Computer techs may use the acronym to describe Remove and Reinstall. Further, statisticians use it to mean Repeatability and Reliability.