What does R stand for?

What does R mean?

R	Runner Governmental » Transportation
R	Runner Community » Sports
R	Rugged Governmental » NASA
R	Refined Business » Products
R	Rounded Academic & Science » Mathematics
R	Retreat Governmental » Military
R	Roster Community » Sports
R	Rechts International » German
R	Rwanda Regional » Countries
R	Risky Business » General
R	Rubbish Miscellaneous » Food
R	Ridiculous Community » Law
R	Restraint Community » Law
R	Resist Governmental » Police
R	Racer Community » Sports
R	Rabbi Community » Synagogues
R	Rook Miscellaneous » Chess
R	Regensburg Regional
R	Rabbi Community » Religion
R	Readiness Governmental » Military
R	Reinforcement Governmental » Military
R	Rei Miscellaneous » Names and Nicknames
R	Reinforcement Community » Educational
R	Resistor Academic & Science » Electronics
R	Respectful Community » Religion