A word, phrase, or symbol which is the subject of a definition, especially in a dictionary entry, or which is introduced into a logical system by being defined.
- ‘The former is defined, by the ancient logic texts I love, as when a definition uses the same terms in the definiens as in the definiendum.’
- ‘He required of definition that the definiens (the statement of definition) should be synonymous with the definiendum (the expression or concept being defined) but contain no terms in common with it.’
- ‘Consider as a definiendum a universal, such as man, and its definiens, rational animal.’
- ‘The more common type,’ referent-based definitions' define the definiendum from the perspective of the entity to which they refer.’
Late 19th century from Latin, ‘that which is to be defined’, from the verb definire (see define).