The term PARTNER OF YIN is represented by the crossword solution YANG, which is a 4-letter word. YANG is one half of the ancient Chinese philosophy of Yin and Yang, which is based on the idea of two complementary forces that exist in all aspects of life. Yin and Yang represent opposite yet interconnected forces that are constantly in flux, and together they form a perfect balance. The Yin is associated with darkness, femininity, and the moon, while the Yang is associated with light, masculinity, and the sun.