Largest named number

The largest finite number with a widely accepted name is the "googolplex": a 1 followed by 10 to the power of 100 zeros (10^10^100), or a 1 followed by a googol of zeros. The term "googol" was coined in 1938 by Milton Sirotta, the nine-year-old nephew of US mathematician Edward Kasner, and Kasner extended it to "googolplex" for this even larger number. The first publication of the word googolplex came in Kasner's 1940 book Mathematics and the Imagination, and it is now listed in the Oxford English Dictionary. Edward Kasner sought to engage children with the joy of mathematics and big numbers, and during a walk in the New Jersey woods with his nephews, he asked for a definition for a 1 followed by 100 zeros; Milton suggested "googol" (a word that would later inspire the search engine name "Google"). Kasner then suggested an ever larger number, which he dubbed the "googolplex", and initially defined it as a 1 followed by as many zeros as it takes to make your arm tired when writing them out. This was later revised to a 1 followed by a googol of zeros.

One can indefinitely raise a number by the power of a newly coined term - for example, the "googolplexian" has been suggested as a name for a 1 followed by a googolplex of zeros, and a name could then be given for a 1 followed by a googolplexian of zeros, and so on - but the "googolplex" has been accepted as a term by the Oxford English Dictionary.