[1] : The Collaborative International Dictionary of English v.0.48

nineteen \nine"teen`\, a. as. nigont=yne, nigont=ene. see
   nine, and ten.
   nine and ten; eighteen and one more; one less than twenty;
   as, nineteen months.
   1913 webster
see also:
nine ten 

[2] : The Collaborative International Dictionary of English v.0.48

nineteen \nine"teen`\, n.
   1. the number greater than eighteen by a unit; the sum of ten
      and nine; nineteen units or objects.
      1913 webster

   2. a symbol for nineteen units, as 19 or xix.
      1913 webster

[3] : WordNet (r) 2.0

nineteen
     adj : being one more than eighteen syn: 19, xix
     n : the cardinal number that is the sum of eighteen and one
         syn: 19, xix
see also:
19 xix xix 

Nineteen >> N Words
Nineteen, definition of term: Nineteen
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