Definitions for undecillionˌʌn dɪˈsɪl yən
Random House Webster's College Dictionary
un•de•cil•lionˌʌn dɪˈsɪl yən(n.)(pl.)-lions; -lion
(n.)a cardinal number represented in the U.S. by 1 followed by 36 zeros, and in Great Britain by 1 followed by 66 zeros.
(adj.)amounting to one undecillion in number.
Origin of undecillion:
1930–35; < L undec(im) eleven (ūn(us) one +-decim, comb. form of decemten ) +-illion, as in million