Meaning

noun (cosmology) the original matter that (according to the big bang theory) existed before the formation of the chemical elements

originResuscitation of Middle English ylem, from Medieval Latin hȳlem, accusative of hȳlē (“matter, the fundamental matter of all things; the matter of the body”) (whence English hyle), a transliteration of Ancient Greek ὕλη (húlē, “wood; material, substance; matter”). The concept of “fundamental matter” – Ancient Greek πρώτη ὕλη (prṓtē húlē) – was propounded by the Greek philosopher Aristotle (384–322…

Etymology from Wiktionary, CC BY-SA 3.0