mukhya

The Muktika canon of 108 Upanishads is headed by 10 Mukhya Upanishads. These are the ten oldest Upanishads, known to and commented upon by the 9th century scholar Shankara. Sanskrit  means "principal", "chief", or "eminent". Also known as Dashopanishads, these ten Mukhya Upanishads probably all predate the Common Era, and they are accepted as śruti by all Hindus. They are listed with their associated Veda :, (ŚYV) "The Inner Ruler" (SV) "Who moves the world?" (KYV) "Death as Teacher", (AV) "The Breath of Life" (AV) "Two modes of Knowing" (AV) "Consciousness and its phases" (KYV) "From Food to Joy", (ṚV) "The Microcosm of Man" (SV) "Song and Sacrifice" (ŚYV)
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Mukhya (Sanskrit) As an adjective, first or primary. In the Puranas, seven creations of Brahma are enumerated, the fourth being called Mukhya, or the fundamental formation, production, or emanation of perceptible beings and things -- the evolution or emanation of the mineral and vegetable kingdoms. This creation is called primary (mukhya), and not secondary, because it relates to the primordial cosmic emanative activities. As such, although the fourth in certain enumerations, it is considered the first as productive of the rupa worlds below. The powers, prakritis, and vikaras beginning with these rupa worlds are alluded to as the secondary emanation.