Stlum

Stlum is a fictional unit of luminous intensity used in speculative fiction, worldbuilding resources, and fan glossaries. It is not a recognized SI unit and has no single formal definition. In different sources, stlum is described as a standardized measure of brightness for virtual displays, scenes in games, or imagined photometric systems. Because it is fictional, the concrete value of 1 stlum may vary by author, ranging from equaling one candela to representing a much larger or smaller quantity.

The name stlum likely derives from standard lumen or is a constructed term in languages used by authors. Some writers treat stlum as a calibrated unit tied to a reference brightness source; others treat it as a purely relative unit used for in-universe comparisons. The lack of a universal standard means definitions can differ between works or between glossaries within a single setting.

Usage and notes: Stlum appears primarily in worldbuilding wikis, game manuals, and fan-fiction glossaries. When encountered, readers should check the source for the exact definition, since there is no universal standard. It is typically used to discuss brightness levels, display calibration, or lighting conditions within a fictional or hypothetical context.

Related concepts include lumen, candela, photometry, and fictional units.