**Defined in theory: Physical-quantities****Source code: physical-quantities.lisp**

**Documentation:**Although it sounds contradictory, a dimensionless-quantity is a quantity whose dimension is the identity-dimension. All numeric tensors, including real numbers, are nondimensional quantities.

**Subclass-Of:**Constant-quantity**Superclass-Of:**Real-number

**Quantity.Dimension:**Identity-dimension

(<=> (Dimensionless-Quantity ?X) (And (Constant-Quantity ?X) (= (Quantity.Dimension ?X) Identity-Dimension)))

**Formerly-Named:**nondimensional-constant-quantity