karma
Karma, in Sanskrit, simply means "action." Roughly understood, it refers to a natural law of causation: actions have effects. It is a central principle in both Hinduism and Buddhism, although it is interpreted differently across various traditions. As a principle, or natural law, karma is the force that drives the cycle of birth and rebirth.
For both Buddhists and Hindus, however, one of the most important aspects of karma is the question of intention. What we do is not as important as the spirit in which we act.