Source : Webster's Revised Unabridged Dictionary (1913)

Fatal \Fa"tal\, a. [L. fatalis, fr. fatum: cf. F. fatal. See
   {Fate}.]
   1. Proceeding from, or appointed by, fate or destiny;
      necessary; inevitable. [R.]

            These thing are fatal and necessary.  --Tillotson.

            It was fatal to the king to fight for his money.
                                                  --Bacon.

   2. Foreboding death or great disaster. [R.]

            That fatal screech owl to our house That nothing
            sung but death to us and ours.        --Shak.

   3. Causing death or destruction; deadly; mortal; destructive;
      calamitous; as, a fatal wound; a fatal disease; a fatal
      day; a fatal error.

Source : WordNet®

fatal
     adj 1: bringing death [ant: {nonfatal}]
     2: having momentous consequences; of decisive importance; "that
        fateful meeting of the U.N. when...it declared war on
        North Korea"- Saturday Rev; "the fatal day of the election
        finally arrived" [syn: {fateful}]
     3: (of events) having extremely unfortunate or dire
        consequences; bringing ruin; "the stock market crashed on
        Black Friday"; "a calamitous defeat"; "the battle was a
        disastrous end to a disastrous campaign"; "such doctrines,
        if true, would be absolutely fatal to my theory"- Charles
        Darwin; "it is fatal to enter any war without the will to
        win it"- Douglas MacArthur; "a fateful error" [syn: {black},
         {calamitous}, {disastrous}, {fateful}]
     4: controlled or decreed by fate; predetermined; "a fatal
        series of events" [syn: {fateful}]

Source : Free On-Line Dictionary of Computing

fatal
     
         Resulting in termination of the program.
     
        (1997-08-03)