Shruti

Shruti ("what is heard") refers to a canon of Hindu religious scripture; all of which have existed (in written form) since, at least, 500 BC. There are 4 sub-categories of Shruti: the Aranyakas, Brahmanas, Vedas, and the Upanishads. Shruti is said to have no author; but rather, are the divine recordings of "cosmic sounds of truth", heard by rishi.

See also: Smriti