• Webster's Revised Unabridged Dictionary
    • Vexillum (Eccl) A banner.
    • Vexillum (Rom. Antiq) A company of troops serving under one standard.
    • Vexillum (Rom. Antiq) A flag or standard.
    • Vexillum (Zoöl) The rhachis and web of a feather taken together; the vane.
    • Vexillum (Eccl) The sign of the cross.
    • Vexillum (Bot) The upper petal of a papilionaceous flower; the standard.
    • ***
Century Dictionary and Cyclopedia
    • n vexillum In Roman antiquity: Strictly, the standard of a maniple; hence, any military standard, whatever its character, except the eagle of the legion.
    • n vexillum The troops collected under a vexillum; a company; a troop; any body of soldiers serving under an ensign separate from that of the legion; hence, under the empire, the body of veteran soldiers connected with a legion who, having served sixteen years in the legion, were detached under a vexillum of their own, with special privileges, for their remaining four years of service. These vexilla averaged from 500 to 600 in strength.
    • n vexillum Eccles.: A processional banner; also, a processional cross.
    • n vexillum A kind of flag or pennon attached by a cord to the upper part of a bishop's pastoral Staff. It is folded round the staff, to prevent the metal of which the staff is made, or with which it is mounted, from being tarnished by the moisture of the hand. Also orarium, sudarium, veil.
    • n vexillum In heraldry, same as banderole, .
    • n vexillum In botany, the standard, or large posterior petal, of a papilionaceous flower. It is external, and wrapped around the others in the bud. Also vexil. See cut under papilionaceous.
    • n vexillum In ornithology, a pogonium. web, or vane of a feather; also, both webs together with the rachis upon which they are borne. Also called standard.
    • ***
Chambers's Twentieth Century Dictionary
    • n Vexillum vek-sil′um in the ancient Roman army, a standard, the troop serving under such a standard: :
    • n Vexillum vek-sil′um (eccles.) a processional banner
    • n Vexillum vek-sil′um (bot.) the large posterior petal of a papilionaceous flower—also Vex′il; the web or vane of a feather
    • ***


Webster's Revised Unabridged Dictionary
L., a standard, a flag
Chambers's Twentieth Century Dictionary
L., 'an ensign'—vehĕre, to carry.


In literature:

The difference in the size of the cells on the calyx under the vexillum right down to the common peduncle is conspicuous.
"More Letters of Charles Darwin Volume II" by Charles Darwin
Vexillum magnum, basi simplici nec auriculata, late ovatum, acutum.
"Expedition into Central Australia" by Charles Sturt
Jussit proeterea Gabrielem vexillum laudis supra Meccanum Templum explicare.
"Thalaba the Destroyer" by Robert Southey

In science:

Let us consider a pair of opposite hole (αααα’, αααα), for instance (2’, 6), and look at a Roman vexillum through the dodecahedron, holding it with αααα’ and αααα parallel, and αααα’ near an eye and αααα opposite. If the dodecahedron is close the eye, we see the two holes. If it is too far, we can see just hole αααα’.
Roman Dodecahedron as dioptron: analysis of freely available data