Definition of ylem in English:

ylem

noun

mass nounAstronomy
  • (in the Big Bang theory) the primordial matter of the universe, originally conceived as composed of neutrons at high temperature and density.

    ‘We had to use primordial ylem.’

Origin

1940s from late Latin hylem (accusative) ‘matter’.

Pronunciation

ylem

/ˈiːlɛm/