a roll or bag, filled with dust, borne by byzantine emperors, as a memento of mortality. it is represented on medals.-a genus of leguminous trees and shrubs. nearly 300 species are australian or polynesian, and have terete or vertically compressed leaf stalks, instead of the bipinnate leaves of the much fewer species of america, africa, etc.  very few are found in temperate climates.-the inspissated juice of several species of acacia; -- called also gum acacia, and gum arabic.