Neutrinos in the Cohesion Unified Field Theory arise from two interacting geometricmechanisms: (1) closure leakage from incomplete n = 6 recursion, and (2) densitydependent propagation governed by the resistance function R(Dst). Closure leakageproduces a small but non-zero recursion-rate deficit, giving neutrinos mass. Densitydependent propagation produces phase drift between partially closed recursion states,giving rise to oscillation. This unified hybrid model explains why neutrinos haveextremely small masses, why there are exactly three neutrino species, why oscillationoccurs, and why oscillation depends on propagation distance and density. The closureleakage parameter ϵ ∼ 10−6–10−7is established as an empirical anchor, consistent withpartial closure geometry, pending first-principles derivation from the torsion intervalstructure of the mass spectrum paper [5]. This is the first geometric, mechanical, andscale-consistent account of neutrino mass and oscillation within the Cohesion UFTframework.