Final answer:
The TLS parameter that refers to the refinement of Anisotropic Displacement Parameters is shape, which looks at the vibrational ellipsoid's changes.
Step-by-step explanation:
The TLS parameter that refers to the refinement of Anisotropic Displacement Parameters (ADP) is shape. Anisotropic Displacement Parameters describe how atoms in a crystal vibrate within the lattice structure. The TLS model divides these vibrations into components related to translation, libration (a type of constrained rotation), and screw-rotation. Specifically, the shape component of the TLS model looks at how the vibrational ellipsoid of an atom changes, indicating how constrained or diffuse its vibration is within the lattice.