Karma is the Sanskrit word for “action” or “doing something.” It comes from an earlier Indo-European word meaning “to make” or “to do”. Karma was a central idea in the Indian religion of Hinduism. People thought that whenever you did anything, it affected your future life, and especially your reincarnation. (Compare this to Taoist or Zen Buddhist ideas in China.)
According to Hindu ideas of karma, if you did something good for other living creatures, you got good karma. This would help you in the future. For instance, if you helped a friend to understand the assignment, you would pile up some good karma. That might make sure the teacher asked you only questions to which you knew the answers. On the other hand, if you did something bad, like killing a spider, you would get bad karma. Maybe when you fell down you would scrape your knee. Americans sometimes say, “What goes around comes around.”
In Hinduism, people saw your karma as something given to you by the gods. The gods decided everything that happened. In Buddhism, though, the gods were left out of it, and karma just happened naturally: good deeds lead to good results, just as apple seeds lead to apple trees. In fact, the whole idea of karma – that it matters whether you are good or bad – may not go back much before the beginnings of Buddhism, maybe about 500 BC. Karma may be an idea that came to India from other cultures. It might have come from Chinese Taoists or Buddhists. They were beginning to visit India at this time as the Silk Road got started.