Chakras are …

The word Chakra ( चक्र ) is Sanskrit which means wheel or disk. The term is now better known as “spiritual centers” or “junctions of energy channels (nāḍī)” derived from a conception of Kundalini yoga and could be located in the human body. According to this conception, there would be seven main chakras and thousands of secondary chakras. This concept is found in the Chudamani Yoga Upanishad (composed between the seventh and tenth centuries) and Yoga Shikha Upanishad.