septendecillion: meaning, definition, pronunciation and examples
C1/C2 (Very Low)Formal, Technical, Literary
Quick answer
What does “septendecillion” mean?
The cardinal number equal to 10^54 (short scale) or 10^102 (long scale), representing an unimaginably large quantity.
Audio
Pronunciation
Definition
Meaning and Definition
The cardinal number equal to 10^54 (short scale) or 10^102 (long scale), representing an unimaginably large quantity.
A term used in theoretical mathematics, cosmology, and occasionally hyperbolic or humorous contexts to denote a quantity of such magnitude that it defies ordinary comprehension.
Dialectal Variation
British vs American Usage
Differences
Historically, the UK used the long scale (10^102), but since the 1970s the short scale (10^54) has become standard in British English for official use, aligning with American usage. Older British texts may still reflect the long scale meaning.
Connotations
Identical: connotes an abstract, almost fantastical magnitude.
Frequency
Equally rare in both dialects. Used almost exclusively in specialized mathematical or cosmological discussions, or as a humorous exaggeration.
Grammar
How to Use “septendecillion” in a Sentence
NUM + ~ (e.g., one septendecillion)~ + of + N (e.g., a septendecillion of atoms)on the order of + a ~Vocabulary
Collocations
Examples
Examples of “septendecillion” in a Sentence
verb
British English
- (No standard verb form exists.)
American English
- (No standard verb form exists.)
adverb
British English
- (No standard adverb form exists.)
American English
- (No standard adverb form exists.)
adjective
British English
- The theoretical model predicted a septendecillion-fold increase in possible states.
- He made a septendecillion-dollar promise, knowing it was pure fantasy.
American English
- We're dealing with septendecillion-level probabilities here.
- Her estimate was off by a septendecillion percent.
Usage
Meaning in Context
Business
Never used in practical finance or business. Potentially used in hyperbolic projections or theoretical economics to illustrate abstract growth models.
Academic
Used in theoretical mathematics, number theory, cosmology (e.g., discussing possible numbers of universes in the multiverse), and combinatorics for illustrative purposes.
Everyday
Virtually never used. If used, it is for deliberate humorous exaggeration (e.g., 'I've told you a septendecillion times!').
Technical
The primary domain. Used to name specific, extremely large orders of magnitude in formal numerical systems and theoretical calculations.
Watch out
Common Mistakes When Using “septendecillion”
- Misspelling (e.g., 'septendecillian', 'septendecilion').
- Using it without clarifying the scale (short vs. long).
- Attempting to use it in any real-world, non-theatrical context.
FAQ
Frequently Asked Questions
In the modern short scale (used by the US, UK, and most English-speaking countries), it is 10^54 (1 followed by 54 zeros). In the traditional long scale (used in much of continental Europe), it is 10^102. Context is crucial.
Almost certainly not. It is a specialist term for theoretical disciplines. Its everyday use is exclusively for humorous exaggeration.
In the short scale, it is octodecillion (10^57), then novemdecillion (10^60), and vigintillion (10^63).
The confusion stems from two different historical naming systems for large numbers (short and long scale), which assign identical names to vastly different quantities. The word itself is also long, complex, and unfamiliar.
The cardinal number equal to 10^54 (short scale) or 10^102 (long scale), representing an unimaginably large quantity.
Septendecillion is usually formal, technical, literary in register.
Septendecillion: in British English it is pronounced /ˌsɛptɛndɪˈsɪljən/, and in American English it is pronounced /ˌsɛptɛndəˈsɪljən/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “Not as rare as a septendecillion (hyperbolic comparison).”
Learning
Memory Aids
Mnemonic
Think: 'SEPTEM' (like September, the 7th month in the old Roman calendar) + 'DEC' (like decade, ten) + 'ILLION' (the suffix for large numbers). It helps recall the short scale pattern where 'n-illion' = 10^(3n+3). Here, 'septendec' suggests 17 (septem=7, dec=10), so 10^(3*17+3) = 10^54.
Conceptual Metaphor
QUANTITY IS SIZE: It conceptualizes amount as physical magnitude, representing the ultimate in vast, immeasurable scale.
Practice
Quiz
In which context is the word 'septendecillion' MOST appropriately used?