Vajrayana Buddhism is an esoteric practice tradition. In the commonest Tibetan analysis, it is one of two practice traditions - the other being the 'Paramitayana' or 'perfection path' - within the Mahayana philosophical approach to the teachings of Gautama Buddha.
The Vajrayana originated as a distinct movement in Indo-Nepal-Tibet region during the Pāla period (8th to 12th centuries), though elements are centuries older, and spread through much of Asia. It is believed that Vajrayana came to existence through the fusion of Mahayana Buddhism and Hinduism. Today it survives as a tradition within Tibetan Buddhism and in Japanese Shingon Buddhism. All major branches of Buddhism also have some elements of esoteric Buddhism. Vajrayana Buddhism is very relevant in Kathmandu, Nepal. The original people of Kathmandu are mainly Hindus and Mahayana Buddhists. It very clearly seen in the festivities and temples, stupas and monasteries of Kathmandu how the two religions have so much in common in both rituals and deities of Tantra.
Vajrayana is also known as Tantric Buddhism. The word 'Vajrayana' comes from 'Vajra' (diamond / thunderbolt) and 'Yana'(path / mode / method). Vajra also denotes the male sexual organ. Therefore the Vajra is meant to signify indestructibility, impetus and creation. It deals with Tantra (magic/unreal) and Mantra (spell).
Teachers of Vajrayana are known as Vajracharya.