Vajra (Skt.; Tib., rdo.rje, ‘diamond’, ‘thunderbolt’).
1. In Hinduism, the weapon of Indra. Although often described as his ‘thunderbolt’, the adamantine (‘diamond’) connections of vajra mean that it is equally described as hard and sharp—the splitter. The association may simply be in the connection between lightning and thunder.

2. Double-headed ritual implement in Tibetan Buddhism, used in conjunction with a bell (Skt., ghaṇṭā; Tib., dril.bu). The bell is always held in the left hand where it represents wisdom, emptiness (śūnyatā) nirvāna, and the feminine principle; the vajra is always held in the right hand where it represents skilful means (upāya-kauśalya), compassion, saṃsāra, and the masculine principle.

vajra in Buddhism and Hinduism, a thunderbolt or mythical weapon, especially one wielded by the god Indra. Being struck by such a weapon is said to bring spiritual illumination.