An indigenous Chinese concept. 1. The two complementary, opposite, and relative modes of existence for any phenomenon. These two modes can be described with lists of correlated qualities: yīn is passive, feminine, dark, and still, whereas yáng is active, masculine, bright, and moving. Chinese have used and continue to use yīn and yáng to explain phenomenon in many ﬁelds of knowledge, including astrology, divination, geomancy, agriculture, medicine, and religion. Yīn and yáng are relative: any phenomenon is both yīn and yáng to some degree, but when paired with something else, one item may be called yīn and the other yáng. So the actual denotations of yīn and yáng are relational and vary greatly according to context. For instance, in Chinese medicine we can say that qì 氣 (energy) is yáng and blood is yīn, that the back of the body is yáng whereas the front in yīn, and that the parts of the body above the waist are yáng whereas those below the waist are yīn. We cannot, however, label the chest in isolation: we can only say that relative to the back, the chest is yīn, but that relative to the thighs it is yáng. 2. The two primordial energies in the universe from which all phenomena evolved.
Yogacara (Consciousness-Only school)
An important school of Mahayana thought that emphasizes that all experience is’ mind only,’ i.e. a creation of the mind. Outside of the knowing process, objects have no reality, and thus the universe is purely mind.