1 A symbol, probably derived from the sun, of the Universal Ruler's (cakravartin's) dominion over the entire earth. As displayed on the palms of his hands (where it may be associated with Viṣṇu's cakra), it is one of the infallible physical signifiers of a cakravartin.
2 As a steel discus, one of the weapons of Viṣṇu, and a symbol of his protective power, placed, iconographically, in his upper right hand. Viṣṇu's cakra is sometimes represented in a personified form (as an āyudhapuruṣa or cakrapuruṣa), and worshipped independently as the god Sudarśana.
3 In Tantra and yoga one a series of ‘wheels’ or centres of spiritual energy spaced along the vertical axis of the subtle body, i.e. along the central channel of the spinal column, known as the suṣumna nāḍī. It is through this, and its related web of veins (nāḍīs), that the prāṇa, the energy or life-force which animates the body, flows. This conception of cakras originated in an unsystematized form in Tantric texts of the 10th and 11th centuries ce, such as the Kubjikāma Tantra (dedicated to the goddess Kubjikā) and the Mālinīvijayottara Tantra, and then spread to most yoga schools, in what became a more or less standardized form of six (plus one) cakras (ṣaṭcakra). According to a formulation used in haṭha-yoga, the cakras are located at the levels of the perineum (the ‘root’ or mūlādhāra cakra), the genital region (the ‘self-based’ or svādhiṣṭhāna cakra), the solar plexus (the ‘gem’ or maṇipūra cakra), the heart (the ‘new’ or anāhata cakra), the throat (the ‘pure’ or viśuddha cakra), between the eyebrows (the ‘understanding’ or ājñā cakra), and at the top of the head (the ‘thousand-petalled lotus’ or sahasrāra cakra). The aim of haṭha-yogic practice is to force the individual's śakti (the serpent power or kuṇḍalinī, which is dormant in the ‘root’ cakra) up the suṣumna, from cakra to cakra, until it merges with the unlimited power of the sahasrāra padma (‘the thousand-petalled lotus’ at the crown of the head) in blissful liberation (envisaged as permanent union with Śiva). The ascension generates ever-increasing spiritual power in the practising yogin. Each cakra is described as a lotus with petals (numbering 4, 6, 10, 12, 16, 2, and 1 000, respectively), and colours, and is assimilated to particular sounds and deities. Quite recently cakras have been integrated into some forms of medical practice.
4 The cakra at the centre of the Indian national flag is based on those found on the lion capital of the Aśokan pillar from Sārnāth. At independence this symbol of an Indian empire replaced the Gandhian spinning wheel that, since 1931, had been at the centre of the flag adopted by the Indian National Congress.
5 In Buddhism, a symbol of the Buddha's dharma or teaching, and especially of his first sermon, hence ‘Dharma Cakra’, the ‘Wheel of the Law’. The Jains also use the wheel to indicate that tīrthaṅkaras teach as well as meditate.
6 The term may also be used of any circular formation or construction, such as a ritual enclosure, and of ritual diagrams, when it is synonymous with the terms maṇḍala or yantra.