An extremely large number. The term was coined by Milton Sirotta, a young nephew of American mathematician Edward Kasner (1878-1955), who said a googol was 1 followed by 100 zeros (10¹⁰⁰). Since a googol is so large that it encompasses everything in the universe and then some, it just means a "gargantuan amount." An even larger amount is a googolplex. See Googleplex and Google.