[tree-di-sil-yuh n]
noun, plural tre·de·cil·lions, (as after a numeral) tre·de·cil·lion.
  1. a cardinal number represented in the U.S. by 1 followed by 42 zeros, and in Great Britain by 1 followed by 78 zeros.
  1. amounting to one tredecillion in number.

Origin of tredecillion

1930–35; < Latin trē(s) three + decillion
Related formstre·de·cil·lionth, adjective, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018