Apeiron (from Greek "unlimited", "indefnite"): the primal matter postulated by the Greek philosopher Anaximander around 600 B.C. as the original matter from which the world, including ►space and ►time, was created.
The apeiron itself was said to be ►eternal and ►infinite, while the world was transient and finite. When material objects cease to exist, they return to the state of apeiron and can be recreated out of it. Apeiron also generates the opposition between warmth and coldness, which was regarded as the ultimate cause for all changes and processes in the universe.
The word "apeiron" originated in the Greek tragedies, where it generally means fates becoming inescapably entangled. Thus the primal matter of the universe was thought of as a fearful disorder, chaos; the Greeks were not sanguine about infinity.