Cybersecurity discourse routinely uses the term "cyber threat" to denote several distinct concepts at once: the cause of a compromise, its outcome, the actor responsible, and the technique employed. This conflation impedes consistent classification, comparable incident documentation, and clear communication of cyber risk between leadership, risk functions, and technical teams. Established frameworks address adjacent layers — control objectives, adversary techniques, software weaknesses, and quantitative risk — but none provides a compact, non-overlapping taxonomy on the cause side that holds stable across system types. The Top Level Cyber Threat Clusters (TLCTC) framework proposes ten top-level threat clusters, each defined by the single generic vulnerability it initially targets. The taxonomy separates threats (causes) from system events, data risk events, business consequences, and actor identity. This paper presents the framework's derivation logic, its design principles and threat topology, the ten cluster definitions, the ten axioms that constrain interpretation, and the classification rules that keep assignment reproducible, together with example mappings expressed in an attack-path notation. By distinguishing a stable strategic management view from a concrete operational security view, TLCTC functions as a translation layer linking strategic risk governance, security operations, and secure software development.