1. Of or pertaining to an ensign or standard.
2. (Science: botany) Of or pertaining to the vexillum, or upper petal of papilionaceous flowers.
(Science: botany) Vexilary aestivation, a mode of aestivation in which one large upper petal folds over, and covers, the other smaller petals, as in most papilionaceous plants.
Origin: Cf. F. Vexillaire, L. Vexillarius a standard bearer.