The addition of particular electrolytes to an aqueous phase in order to increase the distribution ratio of a particular solute.
The addition of electrolytes to improve phase separation behaviour should not be referred to as salting out.
The term is also used for the addition of electrolytes to reduce the mutual partial miscibility of two liquids.
It has no connection with synergism.
PAC, 1993, 65, 2373
(Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993))
on page 2379
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook