ylem Syllabification: (y·lem)Pronunciation: /ˈīləm/Definition of ylem noun Astronomy (in the Big Bang theory) the primordial matter of the universe, originally conceived as composed of neutrons at high temperature and density. Origin: 1940s: from late Latin hylem (accusative) 'matter', from Greek hūlēylem in other Oxford dictionaries Definition of ylem in the British & World English dictionary
