Source : Webster's Revised Unabridged Dictionary (1913)

Insignia \In*sig"ni*a\, n. pl. [L. insigne, pl. insignia, fr.
   insignis distinguished by a mark; pref. in- in + signum a
   mark, sign. See {Ensign}, {Sign}.]
   1. Distinguishing marks of authority, office, or honor;
      badges; tokens; decorations; as, the insignia of royalty
      or of an order.

   2. Typical and characteristic marks or signs, by which
      anything is known or distinguished; as, the insignia of a
      trade.

Source : WordNet®

insignia
     n : a badge worn to show official position