octillion
noun
oc·til·lion äk-ˈtil-yən 
US : a number equal to 1 followed by 27 zeros see Table of Numbers
also, British : a number equal to 1 followed by 48 zeros see Table of Numbers
Example Sentences
Recent Examples on the Web The average human adult is comprised of approximately 7,000,000,000,000,000,000,000,000,000 (7 octillion) atoms. 
Scott Lafee, San Diego Union-Tribune, 5 Apr. 2022 The odds of the suspect not being Blankenship, according to this match, is 1 in 3 octillion. Kevin Grasha, Cincinnati.com, 11 Feb. 2020 To put that in perspective, an octillion is a one with 27 zeros after it. Jared Gilmour, miamiherald, 27 June 2018 The researchers used this tiny deflection to calculate that the mass of Stein 2051B is about 68 percent the mass of our sun — or 1.4 octillion tons (that's 14 followed by 26 zeros). Sarah Kaplan, Washington Post, 13 June 2017
Scott Lafee, San Diego Union-Tribune, 5 Apr. 2022 The odds of the suspect not being Blankenship, according to this match, is 1 in 3 octillion. Kevin Grasha, Cincinnati.com, 11 Feb. 2020 To put that in perspective, an octillion is a one with 27 zeros after it. Jared Gilmour, miamiherald, 27 June 2018 The researchers used this tiny deflection to calculate that the mass of Stein 2051B is about 68 percent the mass of our sun — or 1.4 octillion tons (that's 14 followed by 26 zeros). Sarah Kaplan, Washington Post, 13 June 2017 Word History
Etymology
French, from Middle French, from oct- octa- + -illion (as in million)
First Known Use
1690, in the meaning defined above