Neliöllisen

Neliöllinen is an adjective in Finnish that is formed from the combining form for four (neli-/neljä) and the derivational suffix -llinen, which yields adjectives meaning “having the quality of” or “characterized by.” The genitive singular form of this adjective is neliöllisen. The word thus conveys a sense of “fourfold” or “consisting of four parts,” but its precise meaning depends on context and usage.

In practice, the term is not common in everyday Finnish. For many four-angled or four-sided meanings, standard terminology such as nelikulmainen (quadrilateral) or neliönmuotoinen is preferred. Neliöllinen may appear in historical texts, technical jargon, or stylistic writing, where a speaker or author aims to emphasize a four-part or four-component nature of an object or structure.

Declension follows the pattern of other -llinen adjectives:

- nominative singular: neliöllinen

- genitive singular: neliöllisen

- partitive singular: neliöllistä

- nominative plural: neliölliset

- genitive plural: neliöllisten

- partitive plural: neliöllisiä

Usage notes:

- Because neliöllinen is relatively rare, readers should rely on context to determine its exact scope (four parts, four components, or a fourfold quality).

- When clear geometrical meaning is required, prefer nelikulmainen or other standard terms to avoid ambiguity.

See also: Finnish morphology, -llinen adjectives, geometric terminology in Finnish.