Source : Webster's Revised Unabridged Dictionary (1913)

Zero \Ze"ro\, n.; pl. {Zeros}or {Zeroes}. [F. z['e]ro, from Ar.
   [,c]afrun, [,c]ifrun, empty, a cipher. Cf. {Cipher}.]
   1. (Arith.) A cipher; nothing; naught.

   2. The point from which the graduation of a scale, as of a
      thermometer, commences.

   Note: Zero in the Centigrade, or Celsius thermometer, and in
         the R['e]aumur thermometer, is at the point at which
         water congeals. The zero of the Fahrenheit thermometer
         is fixed at the point at which the mercury stands when
         immersed in a mixture of snow and common salt. In
         Wedgwood's pyrometer, the zero corresponds with
         1077[deg] on the Fahrenheit scale. See Illust. of
         {Thermometer}.

   3. Fig.: The lowest point; the point of exhaustion; as, his
      patience had nearly reached zero.

   {Absolute zero}. See under {Absolute}.

   {Zero method} (Physics), a method of comparing, or measuring,
      forces, electric currents, etc., by so opposing them that
      the pointer of an indicating apparatus, or the needle of a
      galvanometer, remains at, or is brought to, zero, as
      contrasted with methods in which the deflection is
      observed directly; -- called also {null method}.

   {Zero point}, the point indicating zero, or the commencement
      of a scale or reckoning.

Source : WordNet®

zero
     v 1: adjust (an instrument or device) to zero value
     2: adjust (as by firing under test conditions) the zero of (a
        gun); "He zeroed in his rifle at 200 yards" [syn: {zero in}]
     [also: {zeroes} (pl)]

zero
     n 1: a quantity of no importance; "it looked like nothing I had
          ever seen before"; "reduced to nil all the work we had
          done"; "we racked up a pathetic goose egg"; "it was all
          for naught"; "I didn't hear zilch about it" [syn: {nothing},
           {nil}, {nix}, {nada}, {null}, {aught}, {cipher}, {cypher},
           {goose egg}, {naught}, {zilch}, {zip}]
     2: a mathematical element that when added to another number
        yields the same number [syn: {0}, {nought}, {cipher}, {cypher}]
     3: the quantity that registers a reading of zero on a scale
        [syn: {zero point}]
     [also: {zeroes} (pl)]

zero
     adj 1: indicating the absence of any or all units under
            consideration; "a zero score" [syn: {0}]
     2: indicating an initial point or origin
     3: of or relating to the null set (a set with no members)
     4: having no measurable or otherwise determinable value; "the
        goal is zero population growth" [syn: {zero(a)}]
     [also: {zeroes} (pl)]

Source : Free On-Line Dictionary of Computing

ZERO
     
         An {object oriented} extension of {Z}.
     
        ["Object Orientation in Z", S. Stepney et al eds, Springer
        1992].
     
        [{Jargon File}]
     
        (1995-03-30)

zero
     
        1.  0, {ASCI} character 48.  Numeric zero, as
        opposed to the letter "O" (the 15th letter of the English
        alphabet).  In their unmodified forms they look a lot alike,
        and various {kluges} invented to make them visually distinct
        have compounded the confusion.
     
        If your zero is centre-dotted and letter-O is not, or if
        letter-O looks almost rectangular but zero looks more like an
        American football stood on end (or the reverse), you're
        probably looking at a modern character display (though the
        dotted zero seems to have originated as an option on {IBM
        3270} controllers).  If your zero is slashed but letter-O is
        not, you're probably looking at an old-style {ASCII} graphic
        set descended from the default typewheel on the venerable
        {ASR-33} {Teletype} (Scandinavians, for whom slashed-O is a
        letter, curse this arrangement).
     
        If letter-O has a slash across it and the zero does not, your
        display is tuned for a very old convention used at {IBM} and a
        few other early mainframe makers (Scandinavians curse *this*
        arrangement even more, because it means two of their letters
        collide).  Some {Burroughs}/{Unisys} equipment displays a zero
        with a *reversed* slash.  And yet another convention common on
        early {line printers} left zero unornamented but added a tail
        or hook to the letter-O so that it resembled an inverted Q or
        cursive capital letter-O.
     
        [{Jargon File}]
     
        (1995-01-24)
     
        2. To set to zero.  Usually said of small pieces of data, such
        as bits or words (especially in the construction "zero out").
     
        3. To erase; to discard all data from.  Said of disks and
        directories, where "zeroing" need not involve actually writing
        zeroes throughout the area being zeroed.  One may speak of
        something being "logically zeroed" rather than being
        "physically zeroed".
     
        See {scribble}.
     
        (1999-02-07)