H. P. Blavatsky

Mundane Egg. Or any other such symbolical object in the world Mythologies. Meru is a “Mundane Mountain” ; the Bodhi Tree, or Ficus religiosa, is the Mundane Tree of the Buddhists; just as the Yggdrasil is the “Mundane Tree” of the Scandinavians or Norsemen.

Source: H. P. Blavatsky, The Theosophical Glossary, art. Mundane Egg