A low-dimensional descriptor (e.g., distance or angle) used to represent complex, high-dimensional conformational changes.
Dimensionality Reduction: Instead of tracking all coordinates of a system ( atoms), a CV projects this complex space onto a few significant degrees of freedom.
A good CV should clearly distinguish between initial, final, and intermediate states, and capture all slow, relevant motions. Common CVs include interatomic distances, coordination numbers, backbone dihedral angles, or the radius of gyration.