क्षत्रधर्म

Kshatra dharma is the traditional name for the duty of the warrior. It is the tradition's label, not a word that occurs in the Gita. The Gita speaks of the warrior in other terms.

In the second chapter the Lord tells Arjuna that for a warrior there is no greater good than a war on the side of dharma (Gita 2.31). That sentence is spoken to Arjuna about the very war that stands before him. In the eighteenth chapter the actions born of the warrior's nature are listed: valour, splendour, firmness, skill and not fleeing from battle (Gita 18.43).

Common misreading: that kshatra dharma is a general rule to fight, for everyone, in every war.

Better sense: it names the duty that was set before Arjuna in his own situation. The Gita leads it toward being done with the fruit let go and with an even mind in honour and dishonour (Gita 2.38), and it counts non-violence among the divine qualities (Gita 16.2). The wider principle of one's own duty is in Svadharma.

The whole passage can be read in Duty, Honour and Fear.