quantity of dimension one (dimensionless quantity)

https://doi.org/10.1351/goldbook.Q04984
Quantity in the dimensional expression of which all the exponents of the dimensions of the base quantities are zero.
Source:
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 987 [Terms] [Paper]