The relative molecular mass (M r) of a micelle is called the relative micellar mass or micellar weight and is defined as the mass of a mole of micelles divided by the mass of 1/12 mole of
12C.
Source:
PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 612 (https://doi.org/10.1351/pac197231040577)