[ uhn-di-sil-yuh n ]
/ ˌʌn dɪˈsɪl yən /

noun, plural un·de·cil·lions, (as after a numeral) un·de·cil·lion.

a cardinal number represented in the U.S. by 1 followed by 36 zeros, and in Great Britain by 1 followed by 66 zeros.


amounting to one undecillion in number.

Nearby words

  1. undaunting,
  2. undead,
  3. undecagon,
  4. undeceive,
  5. undecided,
  6. undecipherable,
  7. undecisive,
  8. undeclared,
  9. undecylenic acid,
  10. undefeated

Origin of undecillion

1930–35; < Latin undec(im) eleven (ūn(us) one + -decim, combining form of decem ten) + -illion, as in million

Related formsun·de·cil·lionth, adjective, noun

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for undecillion

  • "An undecillion is ten raised to the 36th power," Freddy sighed, fearing that he wasn't getting through to Willy.

    Master of None|Lloyd Neil Goble