資料來源 : WordNet®

natural number
     n : the number 1 and any other number obtained by adding 1 to it
         repeatedly

資料來源 : Free On-Line Dictionary of Computing

natural number
     
         An {integer} greater than or equal to zero.  A
        natural number is an {isomorphism class} of a finite set.
     
        (1995-03-25)