Quin*till"lion (?), n. [Formed fr. L. quintus the fifth, after the analogy of million: cf. F. quintillion. See Quint.] According to the French notation, which is used on the Continent and in America, the cube of a million, or a unit with eighteen ciphers annexed; according to the English notation, a number produced by involving a million to the fifth power, or a unit with thirty ciphers annexed. See the Note under Numeration.