duality/djuːˈalɪti/
noun
1.the quality or condition of being dual.“this duality of purpose was discernible in the appointments”
2.an instance of opposition or contrast between two concepts or two aspects of something; a dualism.“his photographs capitalize on the dualities of light and dark, stillness and movement”সমার্থকশব্দdoubleness, dualism, duplexity, ambivalence, dichotomy, polarity, separation, opposition, difference