Definition of Structured Time

This preprint introduces the Structured Time Model (STM), a theoretical framework by Nathaniel MacDonald proposing that a compactified, curvature-influenced fifth time-like dimension modifies hydrogenic energy levels. The model explains small residuals beyond Dirac-QED using deterministic geometric corrections derived from 5D curvature. This is a work in progress, establishing priority for Structured Time as a physical extension of spacetime. Future work will expand derivations, test broader systems, and unify the framework with QED. © 2025 Nathaniel MacDonald.This work may be shared with attribution but not reused, modified, or republished without explicit permission.