Meaning

noun a cardinal number represented as 1 followed by 100 zeros (ten raised to the power of a hundred)

originCoined by nine-year-old Milton Sirotta in 1920, nephew of American mathematician Edward Kasner, who had asked Milton to think of a name for the 100th power of ten. The word was first published in the book Mathematics and the Imagination (1940).

Etymology from Wiktionary, CC BY-SA 3.0