Definienda

Definienda is the plural of definiendum, a term used in logic and the philosophy of language to designate the words or expressions that are being defined. In a standard definition, two components are typically identified: the definiendum, which is the term whose meaning is being specified, and the definiens, the phrase that supplies the meaning or characterization. When several terms are defined at once, the set of terms that are being defined constitutes the definienda.

Definienda are contrasted with definiens, which functions as the defining content. For example, in the paired elements “Definiendum: planet; Definiens: a celestial body that orbits a star,” the word planet is the definiendum and the accompanying description is the definiens. The plural form, definienda, refers to multiple such terms in a single definitional sequence, such as in a glossary entry that lists several definienda followed by their corresponding definiens.

The notion is primarily used in analytical contexts within philosophy, linguistics, and formal semantics, where precise terminology in definitions is important. It helps distinguish what is being defined from how it is defined and supports careful analysis of the structure and clarity of definitions. While definienda and definiens are standard in technical discussions, ordinary dictionaries and encyclopedias often present definitions without explicitly labeling these components.

In practice, the concept underscores the modular nature of definitions: each definiendum has an accompanying definien that explicates its meaning, and the collection of all definienda in a text is the set of terms under consideration in that definitional section.