Source : Webster's Revised Unabridged Dictionary (1913)

Squadron \Squad"ron\, n. [F. escadron, formerly also esquadron,
   or It. squadrone. See {Squad}.]
   1. Primarily, a square; hence, a square body of troops; a
      body of troops drawn up in a square. [R.]

            Those half-rounding quards Just met, and, closing,
            stood in squadron joined.             --Milton.

   2. (Mil.) A body of cavarly comparising two companies or
      troops, and averging from one hundred and twenty to two
      hundred men.

   3. (Naut.) A detachment of vessels employed on any particular
      service or station, under the command of the senior
      officer; as, the North Atlantic Squadron. --Totten.

   {Flying squadron}, a squadron of observation or practice,
      that cruises rapidly about from place to place. --Ham.
                                                  Nav. Encyc.

Source : WordNet®

squadron
     n 1: a cavalry unit consisting of two or more troops and
          headquarters and supporting arms
     2: an air force unit larger than a flight and smaller than a
        group
     3: a naval unit that is detached from the fleet for a
        particular task