Chakra has two meanings.
(1) Divine disc which can be seen in one of the four hands of Vishnu.

(2) Its another meaning is in context of Yog science. According to it, our body has seven Chakra or seven centers of consciousness located along the spinal column - three in the upper hemisphere of the body and three in the lower hemisphere of the body and one in the center.

(i) Moolaadhaar Chakra - This is the first Chakra located at the base of the spine. This is the root Chakra - the center for the earth element. It is the center that is the base of worship for the Kaulaa school of Tantra.

(ii)  Swaadhishthaan Chakra

(iii) Manipur Chakra - The Chakra which is filled jewels; naval center; the center of the fire element; the solar plexus.

(iv) Anahat Chakra - This is the fourth Chakra in the row which is located in the center, the heart center, and has its location between the upper and lower hemispheres of the body. It is the center of the air element. Practices involving Anahat Chakra are always recommended to control Bhava, which means to balance emotional life as well as the problem of inertia or sleep. If a beginner is not yet competent to meditate on this Chakra, he experiences sleep-like inertia or dozes. Students of Mishra school of Tantra perform their worship at this Chakra.

(v) Vishuddh Chakra - Throat center (above heart); center of the space element.

(vi) Aagyaa Chakra - 

(vii) Sahasraar Chakra - This Chakra is situated at the top and that is why is called Crown Chakra also. The seat, sphere, or abode of Brahm. Also called Brahm Puree.

Bhaagvat 2/1 describes these Chakra's names like this - Manipoorak, Anaahat, Vishuddh, Aagyaa, Sahasraar