duodecillion

noun

duo·​de·​cil·​lion ˌdü-ō-di-ˈsil-yən 

ˌdyü-

often attributive

US : a number equal to 1 followed by 39 zeros see Table of Numbers

also, British : a number equal to 1 followed by 72 zeros see Table of Numbers

Word History

Etymology

Latin duodecim twelve + English -illion (as in million)

First Known Use

1844, in the meaning defined above