This term is not recommended as a synonym for distribution ratio.
Sources:
Orange Book, 2nd ed., p. 89 (https://media.iupac.org/publications/analytical_compendium/)
PAC, 1993, 65, 2373. 'Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993)' on page 2382 (https://doi.org/10.1351/pac199365112373)