Refers to the state of having two fundamental aspects, principles, or natures, often in philosophical or abstract contexts.
This philosophy presupposes the duality of mind and body.
善と悪の二元性は多くの物語のテーマだ。
The duality of good and evil is a theme in many stories.
Compound of 二 (two), 元 (origin, principle), and 性 (nature, quality). The term is a modern Sino-Japanese coinage for 'duality'.