Definitions of r
  1. noun
    the 18th letter of the Roman alphabet
    synonyms: R
    see moresee less
    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
    see moresee less
    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:
    the linear extent in space from one end to the other; the longest dimension of something that is fixed in place
Word Family