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sextillion

/sɛksˈtɪljən/

A number equal to one followed by twenty-one zeros

From Classical Latin sext- (sixth).

noun
adjective
sext-
Classical Latin
Verified
sextus
“sixth”; ordinal form of sex, “six”

from Latin sext- , combining form of sex "six" (see six ) + ending

+1 more source
Classical Latin
Verified
sext-
Combining form meaning “six”

from Latin sext- , combining form of sex "six" (see six ) + ending

+1 more source
English
Verified
sext-
Numerical prefix used in the naming system for large powers

from Latin sext- , combining form of sex "six" (see six ) + ending

+1 more source
-illion
English
AI-inferred
-illion
Number-forming ending modeled on million
English
AI-inferred
-illion
Suffix used in names of successive large numbers
Combined
sextillion
sext- “six” combines with -illion, a large-number naming suffix
English
Verified
sextillion
First attested in the 1680s; originally referred to 10³⁶ in English and Italian systems

from Latin sext- , combining form of sex "six" (see six ) + ending

Modern American English
Verified
sextillion
Usually 10²¹, a short-scale trillion billion

from Latin sext- , combining form of sex "six" (see six ) + ending

Modern English
sextillion

Before it became a playground joke about the sound of “sex,” sextillion was simply a piece of numerical engineering: Latin sextus, “sixth,” was bolted onto the family ending of million. The word appeared in English in the 1680s, and John Locke used it in An Essay Concerning Human Understanding, first published in 1689. But there is a numerical ambush here: in older English and Italian long-scale usage, a sextillion meant 10³⁶, while modern American short-scale usage makes it 10²¹. That is a difference of fifteen zeros—enough to turn a cosmic estimate into an entirely different cosmos. Remember the word as “six meets million,” then check which counting system is holding the ruler.

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