Chi, or universal energy, has different names in different cultures, it is everywhere, anything that is alive needs Chi.
Chi is Chinese name for universal energy; key is Korean name; Parana is Sanskrit name for it and so on, but ultimately, it's a form of energy that can be harnessed by lungs and respiratory system. Chi can be also gained from the air, from the earth, from the sun, moon, and the stars.
Chi can be cultivated, controlled, and can be directed and used in such a discipline like, kung-fu Qigong, fengshui. In most cases Chi (energy) flaws where my mind goes.
The idea of Chi is deep-seated in Chinese culture (Taoism and Buddhism), and consequently, to its martial arts.