I. R¹ , r /ɑː $ ɑːr/ noun (plural R’s, r’s)

1. [uncountable and countable] the 18th letter of the English alphabet

2. [singular, uncountable] American English used to describe a film that has been officially approved as only suitable for people over 17
⇒ THREE R’S

[TahlilGaran] Dictionary of Contemporary English ▲

II. R²

1. American English the written abbreviation of Republican, used after a politician’s name to show that he or she belongs to the Republican Party in the US ⇒ D:
Steve Gunderson (R)

2. British English the written abbreviation of regina (=queen), used after the name of the queen of the United Kingdom:
Elizabeth R

3. (also R.) the written abbreviation of river, used especially on maps
⇒ R & B, R & D, R & R

[TahlilGaran] Dictionary of Contemporary English ▲

R
Are 
Registered Trademark 
Republican 
Restricted Audiences - under 17 years of age not permitted without parent/guardian (movie rating) 
Reverse (automatic transmissions) 
Right

[TahlilGaran] Acronyms and Abbreviations Dictionary ▲