Word Study
zillion
OXFORD DICTIONARY
zillion, n. colloq. an indefinite large number.
Derivative
zillionth adj. & n.
Etymology
Z (perh. = unknown quantity) + MILLION
THESAURUS
zillion
a billion, a crore, a lakh, a million, a myriad, a nonillion, a quadrillion, a thousand, a zillion, astronomical number, billion, considerable, decillion, duodecillion, ever so many, full many, googol, googolplex, heaped-up, infinitude, infinity, jillion, large number, many, million, multifarious, multifold, multiple, multitudinal, multitudinous, myriad, no few, nonillion, not a few, novemdecillion, numerous, octillion, octodecillion, quadrillion, quattuordecillion, quindecillion, quintillion, quite some, septillion, sexdecillion, sextillion, thousand, tredecillion, trillion, undecillion, very many, vigintillionFor further exploring for "zillion" in Webster Dictionary Online