Definition of "octillion"

octillion

/ɒkˈtɪl.iː.ən/

numeral
plural octillions
1. (US, modern British and Australia, short scale) A thousand trillion trillion, a billion billion billion: 1 followed by 27 zeros, 1027.
  Quotations
  Altogether it takes seven billion billion billion (that’s 7,000,000,000,000,000,000,000,000,000, or seven octillion) atoms to make you.
  2019, Bill Bryson, The Body: A Guide for Occupants, Black Swan (2020), pages 5–6
2. (dated British and Australia, long scale) A trillion quintillion: 1 followed by 48 zeros, 1048.