Asat

[ uh-suht ]

/ ˈʌ sʌt /

(in Vedic mythology) the realm of nonexistence, populated by demons.Compare sat²(def 1).

Definition for asat (2 of 2)

[ ey-sat ]

/ ˈeɪˌsæt /

Whatever soul creates in dream is our firm belief, but that remains only for a time being (hence it is asat—non-entity).
The Yoga-Vasishtha Maharamayana of Valmiki, vol. 3 (of 4) part 2 (of 2)|Valmiki
For simplicity's sake, asat will be translated henceforth by non-existing.
The Vedanta-Sutras with the Commentary by Sankaracarya|Translator: George Thibaut