Shruti (Sanskrit: IAST: śrūti) literally means "that which is heard", and refers to the body of most authoritative, ancient sacred texts comprising the central canon of Hinduism. It includes the four Vedas including its four types of embedded texts - the Samhitas, the Brahmanas, the Aranyakas and the early Upanishads.
Shrutis have been considered revealed knowledge, variously described as of divine origin, or nonhuman primordial origins. In Hindu tradition, they have been referred to as Apaurusṣeya (authorless). All six orthodox schools of Hinduism accept the authority of Shruti, but many scholars in these schools denied that Shrutis are divine, work of God. Heterodox schools of Hinduism, such as the 1st millennium BCE Cārvākas, did not accept the authority of the Shrutis and considered them to be the flawed work of man.
Shruti, or "what is heard", differs from other sources of Hindu Philosophy, particularly smriti or text “which is remembered”. These sacred works span much of the history of Hinduism, beginning with the earliest known Hindu Vedic literature and ending in the early historical period with the later Upanishads. Of the Srutis, the Upanishads alone are widely known, and the central ideas of the Upanishadic Sruti are at the spiritual core of Hindus.
Shruti is sometimes spelled sruti or sruthi as in South India.