Source : Webster's Revised Unabridged Dictionary (1913)

Army \Ar"my\, n. [F. arm['e]e, fr. L. armata, fem. of armatus,
   p. p. of armare to arm. Cf. {Armada}.]
   1. A collection or body of men armed for war, esp. one
      organized in companies, battalions, regiments, brigades,
      and divisions, under proper officers.

   2. A body of persons organized for the advancement of a
      cause; as, the Blue Ribbon Army.

   3. A great number; a vast multitude; a host.

            An army of good words.                --Shak.

   {Standing army}, a permanent army of professional soldiers,
      as distinguished from militia or volunteers.

Source : WordNet®

army
     n 1: a permanent organization of the military land forces of a
          nation or state [syn: {regular army}, {ground forces}]
     2: a large number of people united for some specific purpose