the third, mano-maya-kośa, “the sheath made of mind (and the senses) (manas),” together with the fourth, vijñāna-maya-kośa, “the sheath made of understanding,” compose the subtle body, which corresponds to the plane of dream consciousness
Zimmer provides the canonical structural definition of the manomaya kosha as the third of five sheaths, locating it within the subtle body alongside the vijnanamaya kosha and linking it to the dream-consciousness plane of the Mandukya Upanishad.
, Philosophies of India, 1951thesis