Aranyaka

The Aranyakas (Sanskrit आरण्यक ) are part of the Hindu śruti; these religious scriptures are written in early Classical Sanskrit, and form part of either the Brahmanas or Upanishads. "Aranyaka" translates to "the forest books", meaning treatises for sadhus living in the wilderness. This contrasts with the grhyasutras, treatises intended for domestic life.
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Noun
1. a treatise resembling a Brahmana but to be read or expounded by anchorites in the quiet of the forest
(hypernym) Vedic literature, Veda

Aranyaka (Sanskrit) [from aranya forest-like from aranya wilderness, forest] Forest-born; a hermit or holy man who dwells in the forest during the process of becoming a genuine spiritual yogi. Aranyakas (plural) are a class of Vedic treatises of a mystical nature attached to the Brahmanas and closely associated with the Upanishads. They were called such either because they were written in the solitude of the wilderness or because they were intended for study and contemplation by those who had retired from the world to lead the life of spiritual recluses. The Aranyakas are ritualistic, treating of special ceremonies either omitted or dealt with only in part in the Brahmanas, and hence are considered to be supplemental to the latter.
Only four Aranyakas are presently known to exist: the Aitareya (Rig-vedic) forming part of the Aitareya-Brahmana; the Kausitaki (Rig-vedic) whose third and final chapter is the Kanusitaki Upanishad; the Taittiriya, of ten books, belonging to the Yajur-Veda; and the Brihad (Yajur-Veda) which forms a part of the Brihadaranyaka Upanishad attached to the Satapatha-Brahmana.