Source : Webster's Revised Unabridged Dictionary (1913)

N \N\ ([e^]n),
   the fourteenth letter of English alphabet, is a vocal
   consonent, and, in allusion to its mode of formation, is
   called the dentinasal or linguanasal consonent. Its commoner
   sound is that heard in ran, done; but when immediately
   followed in the same word by the sound of g hard or k (as in
   single, sink, conquer), it usually represents the same sound
   as the digraph ng in sing, bring, etc. This is a simple but
   related sound, and is called the gutturo-nasal consonent. See
   {Guide to Pronunciation}, [sect][sect] 243-246.

   Note: The letter N came into English through the Latin and
         Greek from the Ph[oe]nician, which probably derived it
         from the Egyptian as the ultimate origin. It is
         etymologically most closely related to M. See {M}.

N \N\, n. (Print.)
   A measure of space equal to half an M (or em); an en.

Source : WordNet®

N
     n 1: (of a solution) concentration expressed in gram equivalents
          of solute per liter [syn: {normality}]
     2: a common nonmetallic element that is normally a colorless
        odorless tasteless inert diatomic gas; constitutes 78
        percent of the atmosphere by volume; a constituent of all
        living tissues [syn: {nitrogen}, {atomic number 7}]
     3: the cardinal compass point that is at 0 or 360 degrees [syn:
         {north}, {due north}]
     4: a unit of force equal to the force that imparts an
        acceleration of 1 m/sec/sec to a mass of 1 kilogram; equal
        to 100,000 dynes [syn: {newton}]
     5: the 14th letter of the Roman alphabet

Source : Free On-Line Dictionary of Computing

N
     
        /N/ quant. 1. A large and indeterminate number of objects:
        "There were N bugs in that crock!"  Also used in its
        original sense of a variable name: "This crock has N bugs,
        as N goes to infinity."  (The true number of bugs is always
        at least N + 1; see {Lubarsky's Law of Cybernetic
        Entomology}.)
     
        2. A variable whose value is inherited from the current
        context.  For example, when a meal is being ordered at a
        restaurant, N may be understood to mean however many people
        there are at the table.  From the remark "We'd like to order N
        wonton soups and a family dinner for N - 1" you can deduce
        that one person at the table wants to eat only soup, even
        though you don't know how many people there are.
     
        3. "Nth": The ordinal counterpart of N, senses 1 and 2.  "Now
        for the Nth and last time..." In the specific context
        "Nth-year grad student", N is generally assumed to be at least
        4, and is usually 5 or more (see {tenured graduate student}).
        See also {random numbers}, {two-to-the-N}.
     
        [{Jargon File}]