lit. "vital air." From the root word "pran," which means "to breathe." Vital energy. Prana in the human body moves in the pranamaya kosha as five primary life currents known as vayus, "vital airs or winds." These are prana (outgoing breath), apana (incoming breath), vyana (retained breath), udana (ascending breath) and samana (equalizing breath). Each governs crucial bodily functions, and all bodily energies are modifications of these. Usually prana refers to the life principle, but sometimes denotes energy, power or the animating force of the cosmos.