What is karma

Well, while i post this question, to my classmates. I too have questions about the real orgin of karma. You might even say i was curious. As i explore the different websites, im overwhelm of the many definitions of karma. Where does the word karma come from? As im reading about the subject, i realized there is so much information. Hinduism and buddhism, believe that karmsa is the effect of a persons actions. But theres also the Law of Karma and what i believe karma to be. Which is Good Karma Bad Karma. What do you believe karma is?