rate of change ratio

https://doi.org/10.1351/goldbook.R05145
The quotient of two rates where the quantities are of the same kind in the same system for different components: dQ1/dtdQ2/dt For finite time intervals, mean rate of change ratio is: ΔQ1/ΔtΔQ2/Δt=ΔQ1ΔQ2 Δt Rate of change ratio has the dimension one. The denominator is often called the reference quantity. Examples are: mass rate ratio, dm1/dtdm2/dt;
amount of substance
rate ratio, dn1/dtdn2/dt.
Source:
PAC, 1992, 64, 1569. (Quantities and units for metabolic processes as a function of time (IUPAC Recommendations 1992)) on page 1572 [Terms] [Paper]