r

/ɑr/

/ɑ/

Definitions of r

1. noun

   the 18th letter of the Roman alphabet
   synonyms: R

   type of:

   alphabetic character, letter, letter of the alphabet

   the conventional characters of the alphabet used to represent speech
2. noun

   the length of a line segment between the center and circumference of a circle or sphere
   synonyms: radius

   types:

   semidiameter

   the apparent radius of a celestial body when viewed as a disc from the earth

   radius of curvature

   the radius of the circle of curvature; the absolute value of the reciprocal of the curvature of a curve at a given point

   type of:

   length

   the linear extent in space from one end to the other; the longest dimension of something that is fixed in place