septillion

WordNet 3.6
 n septillion the number that is represented as a one followed by 24 zeros
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Webster's Revised Unabridged Dictionary

 n Septillion According to the French method of numeration (which is followed also in the United States), the number expressed by a unit with twentyfour ciphers annexed. According to the English method, the number expressed by a unit with fortytwo ciphers annexed. See Numeration.
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Century Dictionary and Cyclopedia

 n septillion In the British system of numeration, a million raised to the seventh power; a number expressed by unity followed by fortytwo ciphers.
 n septillion In the French numeration, generally taught in the United States, the eighth power of a thousand; a thousand sextillions.
 n septillion The cardinal numeral obtained from a septillion: used like hundred.
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Chambers's Twentieth Century Dictionary

 n Septillion septil′yun the product of a million raised to the seventh power, or a unit with fortytwo ciphers affixed: in the United States, France, &c., the eighth power of a thousand.
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Webster's Revised Unabridged Dictionary
F. septilion, formed fr. L. septem, seven, in imitation of million,
In news:
The chances of this happening are one in 18 septillion.
For a point of reference, there are about one septillion grains of sand on earth.
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