Tantra (Sanskrit: तन्त्र, "loom, warp"; hence "principle, system, doctrine, theory", from the verbal root tan "stretch, extend, expand", and the suffix tra "instrument"), anglicised as tantrism or tantricism, is the name scholars give to a style of religious ritual and meditation that arose in medieval India no later than the fifth century CE, and which came to influence all forms of Indian religious expression to a greater or lesser degree.

The earliest documented use of the word Tantra is in the Hindu text, the Rigveda (X.71.9). The word "Tāntrika" is used for followers of the Tantras in Shaivism, but Buddhist practices based on the Tantras do not use the word Tantric to refer to themselves.

The historical significance of the Tantric method lies in the fact that it impacted every major Indian religion extant in the early medieval period (c. 500 – 1200 CE): thus the Hindu sects of Shaivism, Shaktism and Vaishnavism, as well as Buddhism and Jainism all developed a well-documented body of Tantric practices and related doctrines. Even Islam in India was influenced by Tantra. Tantric ideas and practices spread far outside of India, into Tibet, Nepal, China, Japan, Cambodia, Vietnam, and Indonesia. Today, it is Tibetan Buddhism and various forms of Hinduism that show the strongest Tantric influence, as well as the international postural yoga movement and most forms of American alternative spirituality grouped under the New Age rubric.

Defined primarily as a technique-rich style of spiritual practice, Tantra has no single coherent doctrine; rather, it developed different teachings in connection with the different religions that adopted the Tantric method. These teachings tended to support and validate the practices of Tantra, which in their classical form are more oriented to the married householder than the monastic or solitary renunciant, and thus exhibited what may be called a world-embracing rather than a world-denying character. Thus Tantra, especially in its nondual forms, rejected the renunciant values of Patañjalian yoga, offering instead a vision of the whole of reality as the self-expression of a single, free and blissful Divine Consciousness under whatever name, whether Śiva or Buddha-nature. Since the world was viewed as real, not illusory, this doctrine was a significant innovation over and against previous Indian philosophies, which tended to picture the Divine as absolutely transcendent and/or the world as illusion. The practical consequence of this view was that not only could householders aspire to spiritual liberation in the Tantric system, they were the type of practitioner that most Tantric manuals had in mind. Furthermore, since Tantra dissolved the dichotomy of spiritual versus mundane, practitioners could entail every aspect of their daily lives into their spiritual growth process, seeking to realize the transcendent in the immanent. Tantric spiritual practices and rituals thus aim to bring about an inner realization of the truth that "Nothing exists that is not Divine" (nāśivaṃ vidyate kvacit), bringing freedom from ignorance and from the cycle of suffering (saṃsāra) in the process. In fact, tantric visualizations are said to bring the meditator to the core of his humanity and oneness with transcendence. Tantric meditations do not serve the function of training or practicing extra beliefs or unnatural ways. On the contrary, the transcendence that is reached by such meditative work does not construct anything in the mind of the practitioner, but actually deconstructs all pre-conceived notions of the human condition. The barriers that constrict thinking to limitation-namely, cultural and linguistic frameworks-are completely removed. This allows the person to experience total liberation and then unity with ultimate truth or reality.

Read more about Tantra:  Definitions, History, Practices, Scripture, Relation With Vedic Tradition, Relation To Yoga, Buddhist Tantra, Shaiva Tantra, Evolution and Involution, Ritual Practices, Nyasa, Hindu Tantric Practitioners