Definition of hyperconjugation
: resonance in an organic chemical structure that involves as part of the resonance hybrid the separation of a proton from a methyl or other alkyl group situated next to an electron-deficient unit (as a double bond or carbonium ion), the electrons released by the proton tending to move toward the electron-deficient function with resultant stabilization of the entire structure (as in a trisubstituted propylene H−CH2CR=CR2↔H+CH2=CR−CR2−) — called also
no-bond resonance
