dimensionless adjective2 •Lacking dimensions.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; […] — 1674 •Of a physical constant: lacking units.Iron has a density of 7.8 grams per cubic centimeter: its dimensionless relative density is 7.8.
