Definition of "quintillion" []

• The cardinal number equal to 1018. (noun)
• Chiefly British The cardinal number equal to 1030. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "One quintillion is equal to one billion billion, written as a one followed by 18 zeroes."
• "(An exabyte is 1 quintillion bytes; a quintillion is the number 1 followed by 18 zeroes.)"
• "Professor MORLEY DAVIDSON (Department of Mathematical Sciences, Kent State University): A quintillion is a billion, billion."