This paper introduces Closure Mathematics as a foundational ontological framework for theemergence and organization of mathematical structure. Its central claim is that mathematicsdoes not originate from zero, from arbitrary symbolic convention, or from an isolated axiomatic base alone, but from a deeper pre-scalar condition of isotropic coherence, here termed Zeta Naught. From this condition, mathematical domains emerge through orthogonal differentiation, closure stabilization, and layered structural projection. Within this framework, number systems, algebraic forms, geometric structures, operator spaces, and higher mathematical domains are understood not as disconnected inventions or mere formal extensions, but as orthogonal ontological layers generated through lawful closure processes. Zero is reinterpreted as a coordinate veil rather than an ontological origin; orthogonality becomes the first structural act; and mathematical systems are recast as closureadmissibledomains of coherent form. A formal core is then introduced through a coherence functional, a closure operator, and an associated spectral framework. This formal core recovers several nontrivial mathematicalphysicalstructures, including discrete closure admissibility, the balanced shell degeneracylaw 2ℓ + 1, the minimal gauge-generator hierarchy 1 ⁣ − ⁣3 ⁣ − ⁣8, and a variationalinterpretation of mass as second variation around closure extrema. These results are notpresented as a final completed theory, but as the first mathematically generative spine of awider closure-theoretic program. The paper culminates in the Universal Cohesion Equation and a four-layer ontology consisting of Omnilectic Invariance, Hololectric Field, Relational Structure, and Derived Structure. Closure Mathematics is thus proposed not as a local technique within mathematics, but as a candidatefoundational architecture for understanding mathematical form itself.