What does R stand for?

What does R mean?

R	Are Computing » Texting
R	Review Community » Educational
R	Resources Governmental » Military
R	Right Academic & Science » Mathematics
R	Rate Business » Accounting
R	Read Computing » General
R	Range Governmental » Military
R	Results Business » General
R	Robert Miscellaneous » Names and Nicknames
R	Room Academic & Science » Universities
R	Right Governmental » NASA
R	Range Governmental » NASA
R	Required Governmental » Military
R	Regional Computing » General
R	Return Computing » Assembly
R	Ray Academic & Science » Mathematics
R	Rock Community » Music
R	Relationship Community » Religion
R	Record Business » Accounting
R	Rest Community
R	Resolution Governmental » State & Local
R	Relative Academic & Science » Mathematics
R	Respect Community » Educational
R	Rule Governmental » Military
R	Risk Business » General