Aranyaka is a particular class of Vedic writings, attached to the Brahmanas. The term is sometimes said to be derived from Arani, the rubbing sticks used for igniting sacrificial fires; hence, studies relate to sacrificial rites. More acceptable opinion derives the term from Aranya, 'jungle', hence, treatises are meant to be studied in forest solitudes. The Aranyakas constitute that part of the Vedas which relate to the mystical and esoteric significance of nature and mankind, man's duty in this world and his destiny in the next. They are intended for meditation by anchorites who have retired from the world to live in the forest amid whose silences they may ponder on these mysteries.

Although many passages of the Aranyakas have a boldness and simplicity unmatched in Vedic literature, they are a fragmentary reflections of a mighty age, of which only the memory survives. The Aranyakas are closely linked with the Upanishads, and their names are sometimes interchangeably used. At present only four Aranyakas are extant. The Aitareya, a Rig-vedic Aranyaka forming part of the Aitareya Brahmana. The Kausitaki, also Rig-vedic, consisting of three chapters, of which the third is the Kausitaki Upanishad. The Taittiriya, a Yajur-vedic Aranyaka in ten books. The Brihad, also of the Yajur-veda, forms part of the Brihadaranyaka Upanishad attached to the Satapatha Brahmana. It is attributed to the sage Yajnavalkya. One part of it, called the Yajnavalkya kanda, was probably written after his death, and is devoted to his glorification.