Webster's Revised Unabridged Dictionary · 1913

Octillion

Octillion , noun

[Latin octo eight + -illion, as in English million: compare French octillion.]

According to the French method of numeration (which method is followed also in the United States) the number expressed by a unit with twenty-seven ciphers annexed. According to the English method, the number expressed by a unit with forty-eight ciphers annexed. See Numeration.