The expression coreless planet does not appear in established scientific literature, planetary science textbooks, or reputable encyclopedic references. Consequently, it is not recognized as a formal term within the fields of astronomy or geology.
The phrase is occasionally encountered in speculative contexts—such as science‑fiction narratives, informal discussions, or hypothetical thought experiments—where it is used to describe a planetary body that lacks a differentiated metallic or rocky core. In such usages, the term is typically employed descriptively rather than analytically, to explore the consequences of a planet composed wholly of mantle‑like material, ice, or gas without a central dense region.
Because no peer‑reviewed sources or authoritative encyclopedic entries substantiate the concept, the term remains a non‑standard, informal designation. Any detailed characteristics (e.g., formation mechanisms, internal structure, magnetic field implications) attributed to a “coreless planet” would be speculative and should be treated as such.