- According to the French notation, which is followed
also upon the Continent and in the United States, a unit with fifteen
ciphers annexed; according to the English notation, the number produced
by involving a million to the fourth power, or the number represented
by a unit with twenty-four ciphers annexed. See the Note under
Numeration.
Meaning of 'quadrillion' (Princeton's WordNet)
1 . quadrillion
[ n]
Meaning (1): - the number that is represented as a one followed by 24 zeros