Shruti ("what is heard") is a canon of Hindu scriptures, early forms of which may have existed as early as 1500 BC, with most scholarship favoring dates between 1200 and 800 BC.
Shruti is said to have no author; rather, it is believed to be a divine recording of the "cosmic sounds of truth", heard by rishis.
There are several contesting ways to define Shruti. It is most commonly defined to be composed of the four Vedas:
Some add certain sub-divisions within the Vedas, such as the Aranyakas, Brahmanas, and Upanishads, to the set of works distinctly labeled as Shruti. In addition, the Mahabharata (an Itihasa, or History, also part of the "friendly scripture" class) is considered by some to be Shruti and is sometimes called the fifth Veda. Sometimes the Bhagavad Gita, a chapter within the Mahabharata, is separately considered as worthy of the Shruti status.
Important Hindu scriptures that are not considered Shruti are called Smriti.
