Vyuha (vyūha)

A vyuha is a battle formation, arranged each morning by the commander and named for the shape it takes: the needle, the eagle, the crocodile, the crescent, the lotus. The Mahabharata treats formation as the intellectual core of warfare, and much of the war narrative is a contest between an array and the counter-array set against it. Knowing how to enter and how to leave a given vyuha is specialist knowledge, which is why Abhimanyu's half-learned lesson kills him.