Avastha a Sanskrit term meaning condition and state. It is a vedanta concept implying a state of consciousness or condition in a loka, bhuvana, or world. In the upanisads, notably the Mandukya Upanisad, the concept is defined as four levels of consciousness: jagrat (waking), svapna (dreaming), susupti (deep sleep) and turiya (state of communion with the infinite).
Through yoga, turiya is attained which is a concentrated absorption (samadhi), sometimes equated with liberation (moksa). In the Mandukya Upanisad the three states of consciousness correspond to the three levels of the hierarchical cosmos and the three levels of the sound of om. The fourth avastha or state corresponds to Brahman, the absolute. The idea expressed by the avasthas corresponds to cosmology. Avastha also refers to the four stages of human existence: childhood, youth, adulthood and old age. [Sirajul Islam]