definii

Definii is a term used in speculative discussions of definitions and formal semantics to denote the set of terms that have been defined within a definitional system. The concept is not widely standardized and appears mainly in thought experiments and analytic debates about how definitions organize meaning. The word is inspired by the Latin definire, meaning to define, with an adapted plural or collective form to indicate a collection of defined terms.

In this usage, definii are often studied in relation to the defining expressions used to introduce them. Researchers typically distinguish the single term that is being defined (the definiendum) and the defining part (the definiens), while using definii to refer to the aggregate of all definienda within a system. This perspective allows examination of how the choice and arrangement of definitions affect clarity, inference, and knowledge representation.

Applications and relevance span philosophy of language, formal semantics, lexicography, and knowledge engineering. In dictionaries and terminological databases, the notion of definii helps model how terms are grouped by definitional type, scope, or source. In artificial intelligence and explainable AI, examining definii can illuminate how a system justifies its assertions and how changes to definitions propagate through a knowledge graph or ontology.

History and reception: the term definii emerged in contemporary theoretical discussions as a convenient shorthand for collections of defined terms within a framework. It remains a niche concept, used to probe issues of definitional stability, scope, and definitional chaining. See also: definiendum, definiens, definition, lexicography, terminology.