\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.