- a cardinal number represented in the U.S. by 1 followed by 57 zeros, and in Great Britain by 1 followed by 108 zeros.
- amounting to one octodecillion in number.
Origin of octodecillion
1935–40; < Latin octōdec(im) eighteen + English -illion, as in million
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018