solubility

https://doi.org/10.1351/goldbook.S05740
The analytical composition of a saturated solution, expressed in terms of the proportion of a designated solute in a designated solvent, is the solubility of that solute. The solubility may be expressed as a concentration, molality, mole fraction, mole ratio, etc.
Source:
Orange Book, 2nd ed., p. 84 (http://media.iupac.org/publications/analytical_compendium/)