The volume from which a macromolecule in a @D01739@ of a macromolecule effectively excludes all other macromolecules. The excluded volume of a macromolecule depends on the Gibbs and Helmholtz energies of mixing of solvent and polymer, i.e. on the thermodynamic quality of the solvent, and is not a measure of the geometrical volume of that macromolecule.