Definition of septillion in English:


cardinal numberseptillions

  • 1A thousand raised to the eighth power (10²⁴).

    Compare with quadrillion

    ‘This is a septillion times longer than the current age of the universe.’
    • ‘Translated into arithmetical terms, the result is 79 octillion, 228 septillion, 162 sextillion, 514 quintillion, 270 quadrillion with 15 zeros attached; that is 79,228,162,270,000,000,000,000,000.’
    • ‘Naturally occurring wormholes, if they exist at all, are likely to be extremely small, about 10 septillion times smaller than a typical atom.’
    • ‘That, he says, ‘comes to only 1.6807 septillion languages.’’
    1. 1.1mainly British dated A million raised to the seventh power (10⁴²).



/sepˈtilyən/ /sɛpˈtɪljən/


Late 17th century from French, from million, by substitution of the prefix septi- ‘seven’ (from Latin septimus ‘seventh’) for the initial letters.