真言

True words, words of Truth, the words of the Tathāgata, Buddha-truth. The term is used for (sa) mantra, and (sa) dhāraṇī, indicating magical formulae, spells, charms, esoteric words. Buddhas and Bodhisattvas have each an esoteric sound represented by a Sanskrit letter, the primary Vairocana letter, the alpha of all sounds being 'a' 阿, which is also styled 真言救世者 the True World that saves the world.