(Greek = unlimited or infinite — from a, without and peirar, limit)
Anaximander's boundless primordial substance from which everything we perceive is derived.
1. The pre-Socratics sought the element that constitutes all things. Thales thought it was water, Anaximenes claimed it was air, and Anaximander thought it was the apeiron, a substance that was subject to neither age nor decay.