The Collaborative International Dictionary of English v.0.48:

Vexillar \Vex"il*lar\, Vexillary \Vex"il*la*ry\, [Cf. F.
   vexillaire, L. vexillarius a standard bearer.]
   [1913 Webster]
   1. Of or pertaining to an ensign or standard.
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   2. (Bot.) Of or pertaining to the vexillum, or upper petal of
      papilionaceous flowers.
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   Vexilary aestivation (Bot.), a mode of aestivation in which
      one large upper petal folds over, and covers, the other
      smaller petals, as in most papilionaceous plants.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Vexillary \Vex"il*la*ry\, n. [L. vexillarius: cf. F.
   vexillaire.]
   A standard bearer. --Tennyson.
   [1913 Webster]