decisum

Decisum is a term that may refer to a decision or ruling, primarily when encountered in Latin-language legal or philosophical texts. Derived from the Latin decisum, the neuter past participle of decidere, meaning “that which has been decided,” the word has historically denoted a judgment issued by a court or authority.

In medieval and early modern legal literature, decisum appeared as a formal designation of a decision. It could appear in citations or as part of a longer phrase indicating the outcome of a dispute. In modern English-language law, the Latin term is rarely used outside historical contexts; contemporary jurisprudence typically uses “decision” or “judgment.”

Outside legal history, decisum is not a standard term in formal philosophy or decision theory. Some writers may use Latinized forms for rhetorical or stylistic purposes or as a proper noun in product names or organizational titles. As a result, the meaning of decisum can vary with context, and there is no single universal definition in contemporary discourse.

When encountered in texts, it is helpful to look for surrounding clues: whether it is part of a Latin sentence, a citation of a court’s ruling, or a modern discussion that uses the term metaphorically to mean a concluded choice.