Yang refers to things or substances opposite to yin. It is characterized by restlessness, production, clearing, descent, energy engenderment, and transformation. Generally, yang stands for lightness, clearness, function, hyperactivity, motility, upwardness, or hotness. There are two meanings of the term. First, yang as opposed to yin works together with yin as a duality to divide everything in the universe in terms of time, space, and nature. Second, it refers to yang qi which constitutes the original qi of cosmic forces or qi of human life together with yin qi.