dimensionless

dimension +‎ -less

dimensionless (not comparable)

1. Lacking dimensions.

   Synonym: adimensional

   • 1674, John Milton, Paradise Lost, Book 11, lines ,

     […] To Heav’n thir prayers

     Flew up, nor missd the way, by envious windes

     Blow’n vagabond or frustrate: in they passd

     Dimentionless through Heav’nly dores […]

   • 1771, William Kenrick, A Lecture on Perpetual Motion, London, for the author, Introduction, p. 15,

     Extended objects may be separated by dimensionless points; but dimensionless points cannot be separated, but by some real distance, or something really extended.

   • 1930, E. E. Smith, Skylark Three, Fantasy Press, 1948, Chapter 3,

     They saw the utter, absolute darkness of the complete absence of all light; and upon that indescribable blackness they beheld superimposed the almost unbearable brilliance of enormous suns concentrated into mathematical points, dimensionless.

   • 1932, William Faulkner, Light in August, New York: Modern Library, 1950, Chapter 10, pp. 199-200,

     He did not look once again toward the dark house. […] He simply went quietly as if that were his natural manner of moving and passed around the now dimensionless bulk of the house, toward the rear, where the kitchen would be.

2. (sciences) (of a physical constant) Lacking units.

   Iron has a density of 7.8g/cc: its dimensionless relative density is 7.8.

• dimensionless quantity