The distribution coefficient of a molecule is a measure of its solubility in two immiscible phases, typically a hydrophobic organic solvent and water. It is defined as the ratio of the concentration of the molecule in one of the phases to its concentration in the other phase at equilibrium. This coefficient can vary depending on factors such as pH, temperature, and the nature and concentration of the solvent and solute. Consequently, it is often used as a tool for drug development, in analytical chemistry, and in the study of environmental pollutants.