This paper investigates the propagation of neutrinos in a curved spacetime background. Following from this, we propose a novel mechanism for generating their masses via gravity-embedded Weinberg operator. This model arises from a hitherto unexplored interaction between gravitational field and the Majorana-neutrino fields. Two distinct methods, each, of calculating dimensionless gravitational couplings from a gravitational field and spontaneous-symmetry-breaking mass-scale of high-energ...