Vĕx'il-lar or Vĕx'il-la-ry, a.

a. [Fr. vexillaire, It. vessillario. See supra.]

1. Of, or pertaining to, an ensign or standard.
2. (Bot.) (a.) Of, or pertaining to, the vexillum, or upper petal of papilionaceous flowers. (b.) Of, or pertaining to, a mode of estivation in which the exterior petal, as in the case of the vexillum, is largest, and incloses and folds over the other petals.