Mantrayana

mantrayāna (T. sngags kyi theg pa; C. zhenyan sheng; J. shingonjō; K. chinŏn sŭng 眞言乘). Literally, "vehicle of mantra". One of multiple names for the practice of tantra within the Mahayana tradition, along with mantranaya, vajrayana, tantrayana, etc.

"In Tibetan Buddhism, the Tibetan forms of the terms mantrayāna and guhyamantrayāna (“secret mantra vehicle”) are used as commonly as vajrayāna and more commonly than tantrayana."

Vesna Wallace states:

As attested in many tantric sources, the terms Mantrayāna, Mantranaya, Mantranīta, and Mantramārga are employed interchangeably.

Further reading

• tantra

Sources

• Buswell, Robert E.; Lopez, Donald S. (2014), The Princeton Dictionary of Buddhism, Princeton University 
• Vesna A. Wallace, “A Brief Exploration of Late Indian Buddhist Exegeses of the ‘Mantrayāna’ and ‘Mantranaya’.” Pacific World: Journal of the Institute of Buddhist Studies 13, 2011, pp. 95–112.