Definition of "vajra"

vajra

noun
countable and uncountable, plural vajras
1. (countable) A Buddhist ceremonial mace and symbol, usually interpreted as both a diamond and a thunderbolt.
  Quotations
  At the centre is a five-pronged vajra draped and bound with a coloured silk scarf, representing one of the Five Buddha wisdoms or activities.
  2004, Robert Beér, The Encyclopedia of Tibetan Symbols and Motifs, page 239
2. (uncountable) One of the five central Buddhist principles, representing indestructible substance that cuts and penetrates through emotional instability or uncertainty.
  Quotations
  Those five principles or buddha families are called vajra, ratna, padma, karma, and buddha.
  1981, Chögyam Trungpa, Journey Without Goal: The Tantric Wisdom of the Buddha, page 78
3. (Rigveda, Hindu mythology) The weapon of Indra, the god of heaven and the chief deity of the Rigvedic pantheon, used to kill sinners and ignorant persons.