Numericon gives the history of the words googol and googolplex:
… the famous googol, 10100 (a 1 followed by 100 zeros), defined in 1929 by American mathematician Edward Kasner and named by his nine-year-old nephew, Milton Sirotta. Milton went even further and came up with the googolplex, now defined as 10googol but initially defined by Milton as a 1, followed by writing zeros until you get tired.
Related post: There isn’t a googol of anything
Apologies that there isn’t much mathematical significance in this post, but recall Doc Brown from Back to the Future Part 3, “Sarah, was one in a million…, one in a billion…, one in a googolplex.” Doc was sent back in time, to a time before the googol was ever defined, let alone the googolplex.
Even more interesting is that the Google search engine founded its name by a Stanford graduate student accidentally typing “google” instead of googol, and hence the name Google was founded — coincidentally, Google’s headquarters in Mountain View has been named as Googleplex.