Every science has its own exclusive terminology. The science of music has many different Ragas, Shrutis, Layas, and Talas. Similarly, the science of meditation has its own terminology. Chakras are one such terminology. Meditators will often start perceiving energy movements in their bodies that correspond to Chakras. One of the Good places to read about Chakras is this article on Deepak Chopra's website : http://www.chopra.com/articles/what-is-a-chakra.
