Helicity may refer to: Helicity (fluid mechanics), the extent to which corkscrew-like motion occurs Helicity (particle physics), the projection of the spin onto the direction of momentum Magnetic helicity, the extent to which a magnetic field "wraps around itself" Circular dichroism, the differential absorption of left and right circularly polarized light A form of axial chirality A former name for inherent chirality See also Helix