noun, often attributive un·de·cil·lion \ˌən-di-ˈsil-yən\

Definition of undecillion

  1. US :  a number equal to 1 followed by 36 zeros — see number table; also, British :  a number equal to 1 followed by 66 zeros — see number table

Origin and Etymology of undecillion

Latin undecim eleven (from unus one + decem ten) + English -illion (as in million) — more at one, ten

First Known Use: 1844

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