A dimensionless quantity is a physical or mathematical quantity invariant under a change of the chosen measurement units. In dimensional analysis it has dimension vector zero and can be expressed as a ratio or product in which all base-unit exponents cancel. Buckingham's pi theorem organizes relations among quantities into independent dimensionless products (Buckingham 1914).
Dimensionless Quantity
See also
Dimensional AnalysisExplore with Wolfram|Alpha
References
Buckingham, E. "On Physically Similar Systems; Illustrations of the Use of Dimensional Equations." Phys. Rev. 4, 345-376, 1914. https://doi.org/10.1103/PhysRev.4.345.Cite this as:
Weisstein, Eric W. "Dimensionless Quantity." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/DimensionlessQuantity.html