\Quad*ril"lion\, n. [F., fr. L. quater four times,
akin to quattuor four, E. four; -- formed like million. See
{Four}, {Million}.]
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}.