a grouping of the melakarta raagas into groups of six raagas. They are grouped according to which combination of ri and ga they have. Within a cakra, the first raaga has D1 and N1, the second has D1 and N2, the third has D1 and N3, the fourth has D2 and N2, the fifth has D2 and N3, and the last has D3 and N3. There are 12 cakras, 6 with M1 and 6 with M2, giving (6 * 12) 72 melakartas. The cakras are indu, nEtra, agni, vEda, bana, rutu, rishi, vaasu, brahma, disi, rudra, and aaditya. For details, go here
Any of the six centers of spiritual power located in the body; these are identified with specific deities and can be accessed through certain exercises. (Also Kalachakra, JP XIV; Karma Triyana Dharmachakra, CK VII.)