Source : Webster's Revised Unabridged Dictionary (1913)

Vexillum \Vex*il"lum\, n.; pl. {Vexilla}. [L., a standard, a
   flag.]
   1. (Rom. Antiq.)
      (a) A flag or standard.
      (b) A company of troops serving under one standard.

   2. (Eccl.)
      (a) A banner.
      (b) The sign of the cross.

   3. (Bot.) The upper petal of a papilionaceous flower; the
      standard.

   4. (Zo["o]l.) The rhachis and web of a feather taken
      together; the vane.