DuckCorp Dico

Found 2 definitions

1.                 From Japanese-English FreeDict Dictionary ver. 0.1:
                   
   
   
                   
                     
   Ｒ /lˈe̞təˈe̞fˈe̞fɡˈo̞nˈiː/, ｒ /lˈe̞təˈe̞fˈe̞fɡˈo̞nˈiː/, アール /ˈääɽɯᵝ/
   1. (noun (common) (futsuumeishi))
   R, r
   2.  [mathematics]  (esp. ｒ)
   radius
   3.
            Note: word usually written using kana alonecurve
   
                   
                 

2.                 From Japanese-English FreeDict Dictionary ver. 0.1:
                   
   
   
                   
                     
   Ｒ /lˈe̞təˈe̞fˈe̞fɡˈo̞nˈiː/, ｒ /lˈe̞təˈe̞fˈe̞fɡˈo̞nˈiː/, アール /ˈääɽɯᵝ/
   1. (noun (common) (futsuumeishi))
   R, r
   2.  [mathematics]  (esp. ｒ)
   radius
   3.
            Note: word usually written using kana alonecurve