noun Mathematics.

the cardinal number of the set of all positive integers; the smallest transfinite cardinal number.

Nearby words

  1. alene,
  2. alençon,
  3. alençon lace,
  4. aleph,
  5. aleph-bet,
  6. alepoudelis, odysseus,
  7. aleppo,
  8. aleppo boil,
  9. aleppo gall,
  10. aleppo pine

Origin of aleph-null

First recorded in 1905–10

Also called a·leph-ze·ro [ah-lif-zeer-oh] /ˈɑ lɪfˈzɪər oʊ/. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for aleph-null




the smallest infinite cardinal number; the cardinal number of the set of positive integersSymbol: א 0
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

Science definitions for aleph-null



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