• synonyms


noun Mathematics.
  1. the cardinal number of the set of all positive integers; the smallest transfinite cardinal number.
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Origin of aleph-null

First recorded in 1905–10
Also called a·leph-ze·ro [ah-lif-zeer-oh] /ˈɑ lɪfˈzɪər oʊ/.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for aleph-null



  1. the smallest infinite cardinal number; the cardinal number of the set of positive integersSymbol: א 0
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

aleph-null in Science


  1. The first of the transfinite cardinal numbers, corresponding to the number of elements in the set of positive integers.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.