kolmiopintaista
Kolmiopintaista is a Finnish adjective used to describe something that has or presents three surfaces. The form kolmiopintaista is the inflected form used in contexts requiring the partitive singular, while the base adjective is kolmiopintainen. The word is built from kolmi- (three) and pinta (surface) with a common adjectival suffix.
The term is specialized and relatively rare in everyday Finnish. It appears mainly in technical, architectural,
Geometric note: a closed solid with exactly three planar surfaces is degenerate in ordinary three-dimensional space,