The term preferred by Schoenberg to describe his style of composition beginning around 1908, in which no particular tonal centricity is in evidence, all 12 tones of the 12-edo chromatic scale being used freely.
This style of musical composition was dubbed "atonal" by most commentators, a term which Schoenberg never liked.
For a detailed exploration, see Monzo, Searching for Schönberg's Pantonality.