Googol

"According to the story, Kasner asked his nephew Milton Sirotta, who was then 8 years old, what name he would give to a really large number, and "googol" was Milton's response. In the traditional American system for naming large numbers, the googol (1 followed by 100 zeroes) is equal to 10 duotrigintillion."

From How Many? A Dictionary of Units of Measurement