Source: Wiki
The Vedas depict Brahman as the Ultimate Reality, the Absolute or Paramātman (Universal Self). Brahman is the indescribable, inexhaustible, incorporeal, omniscient, omnipresent, original, first, eternal, both transcendent and immanent, absolute infinite existence, and the ultimate principle who is without a beginning, without an end , who is hidden in all and who is the cause, source, material and effect of all creation known, unknown and yet to happen in the entire universe.
Brahman (not to be confused with the deity Brahmā) is seen as a Cosmic Spirit. The personality behind Brahman is known as Parabrahman (The superior Brahman). Brahman may be viewed as Nirguna Brahman (without personal attributes) or Saguna Brahman (with attributes).