There are many conceptions of The Absolute in various fields and subjects, such as philosophy, religion, spiritual traditions, mathematics, and even natural science. The nature of these conceptions can range from "merely" encompassing all physical existence, nature, or reality, to being completely unconditioned existentially, transcending all concepts, notions, and types, kinds, and categories of being.
The Absolute is often thought of as causing to come into being manifestations that interact with lower or lesser forms of being. This is either done passively, through emanations, or actively, through avatars and incarnations. These existential manifestations, which themselves can possess transcendent attributes, only contain minuscule or infinitesimal portions of the true essence of The Absolute.
The term itself was not in use in ancient or medieval philosophy, but closely related to the description of God as Actus purus (Pure Actuality) in scholasticism. It was introduced in modern philosophy, notably by Hegel, for "the sum of all being, actual and potential". The term has since also been adopted in perennial philosophy.
There are three general ways of conceiving the Absolute. The Absolute might be (1) the first and greatest being, (2) not a being at all but the "ground" of being, or (3) both the ground of being and a being.
In conception one the Absolute is the most true and intelligible reality. It can be spoken of and known. For example, Georg Wilhelm Friedrich Hegel's Absolute Spirit is the most true reality. It is thinkable, speakable, and exists in the objective world by comprehending everything, including people, states, and world history.