Such was the name that physicist Max Born gave to the 'primordial substance' that his colleague Werner Heisenberg concluded was the original substance whence all elementary particles derived. The term is the Greek for 'unlimited', thereby denoting a substance always in existence that generates different quantum states and manifestations, which then dissipate.
Max Born, however, was also paying homage to pre-Socratic philosopher Anaximander, who also hypothesized a 'primordial matter' that both generated different infinite worlds and pulled them apart, by a cycle of birth and decay. Anaximander lived in the sixth century BCE.
This theory was taken up by Lucretius, Roman Epicurean and atomist philosopher of the first century BCE. At the end of the second book of his exquisite de Rerum Natura (1023-1174), operating from the premise that the universe is infinite, Lucretius argues that it is just not logical to suppose that only the world in which he lives has been created. Such creations are the result of collisions and fissures of matter.
Max Born knew well that the embryos of these theories came from the Classical past and his acknowledgement of this debt made me smile. Ancient science is one of my great loves. When you see the sophistication and endurance of some of their ideas, I think you will understand why.