helicityPronunciation: /hiːˈlɪsɪti/Definition of helicity noun [mass noun] 1chiefly Biochemistry helical character, especially of DNA. 2 Physics a combination of the spin and the linear motion of a subatomic particle. Origin: 1950s (in helicity (sense 2)): from Latin helix, helic- 'spiral' + -ityhelicity in other Oxford dictionaries Definition of helicity in the US English dictionary