[1] : The Collaborative International Dictionary of English v.0.48

quadrillion \quadril"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.
   1913 webster quadrilobate
see also:
four million numeration 

[2] : WordNet (r) 2.0

quadrillion
     n 1: the number that is represented as a one followed by 24
          zeros; "in england they call a septillion a quadrillion"
     2: the number that is represented as a one followed by 15 zeros

[3] : Moby Thesaurus II by Grady Ward, 1.0

29 moby thesaurus words for "quadrillion":
   a billion, a crore, a lakh, a million, a myriad, a nonillion,
   a quadrillion, a thousand, a zillion, decillion, duodecillion,
   googol, googolplex, jillion, nonillion, novemdecillion, octillion,
   octodecillion, quattuordecillion, quindecillion, quintillion,
   septillion, sexdecillion, sextillion, tredecillion, trillion,
   undecillion, vigintillion, zillion

Quadrillion >> Q Words
Quadrillion, definition of term: Quadrillion
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