Prana
प्राण (prāṇa)
The breath of life - the vital current the traditions track through breath, and train by way of it. Read in English
प्राण — जीवन की श्वास; वह ऊर्जा-धारा जिसे परंपराएँ श्वास में देखती और श्वास से साधती हैं।
Prana is life-force, and its most public face is the breath. The Upanishads tell a parable in which the faculties argue over which is supreme; each departs in turn and life continues - until prana rises to leave, and every other power is dragged after it. The argument ends.
Whether one takes prana as subtle physiology or as poetry for the autonomic nervous system, the practical fact holds: the breath is the one vital process both automatic and trainable, a handle on states that refuse direct command.
Hence the traditions' obsessive attention to it. Before techniques, simple literacy helps: noticing that anger shortens breath, that grief interrupts it, that attention and breath steady together. The breath is a gauge long before it is a lever.