liquid-liquid extraction

This term may be used in place of liquid-liquid distribution when the emphasis is on the analyte(s) being distributed (or extracted).
The distinction between the distribution constant(K D) and the partition constant(K D o) or the concentration distribution ratio (D c) is reaffirmed and it is recommended that the terms partition constant, partition coefficient and extinction constant should not be used as synonyms for the (analytical) distribution ratio, D c. A distinction is drawn between the terms solvent and diluent, and the term extractant is now restricted to the active substance in the solvent (i.e. the homogeneous 'organic phase' which comprises the extractant, the diluent and/or the modifier) which is primarily responsible for the transfer of solute from the 'aqueous' to the 'organic' phase.
Orange Book, p. 88