Googol

In 1920, American mathematician Edward Kasner asked his nine-year-old nephew Milton Sirotta to invent a name for the number 1 followed by 100 zeros. The boy said "googol." No etymology, no Latin root, no Greek prefix. A child's nonsense syllable became a mathematical term that Kasner published in his 1940 book Mathematics and the Imagination.

The number itself is staggeringly large. The observable universe contains roughly 10^80 atoms. A googol is 10^100—twenty orders of magnitude larger than everything that physically exists. Kasner used it to illustrate the difference between an unimaginably large number and infinity. A googol is finite. It just doesn't correspond to anything real.

Kasner also asked Milton about a googol raised to the power of a googol—10^googol. Milton called it a "googolplex." Kasner noted that you couldn't write out a googolplex even if you used every particle in the universe as ink. The number exists only as notation.

In 1997, Larry Page and Sergey Brin named their search engine BackRub. A year later, they renamed it Google—a misspelling of googol that stuck. They wanted a name suggesting vast quantities of information. The domain google.com was available; googol.com was not. A typo turned a child's invented word into one of the most recognized brands in history.