Effects of past actions, from this or previous lifetimes; from the Sanskrit kri, to do. The equilibrating law of karma, as expounded in the Hindu scriptures, is that of action and reaction, cause and effect, sowing and reaping. In the course of natural righteousness, each man by his thoughts and actions becomes the molder of his destiny. Whatever energies he himself, wisely or unwisely, has set in motion must return to him as their starting point, like a circle inexorably completing itself. An understanding of karma as the law of justice serves to free the human mind from resentment against God and man. A man's karma follows him from incarnation to incarnation until fulfilled or spiritually transcended.
The cumulative actions of human beings within communities, nations, or the world as a whole constitute mass karma, which produces local or far-ranging effects according to the degree and preponderance of good or evil. The thoughts and actions of every man, therefore, contribute to the good or ill of this world and all peoples in it.
PY: Karma means material action, that which is instigated by egoistic desire. It sets into motion the law of cause and effect. The action produces a result that binds itself to the doer until the cause is compensated by the appropriate effect, whether forthcoming immediately or carried over from one life to another.