Gammadia (γαμμάδια, for γαμμάτια), a cruciform ornament, embroidered on the borders or woven into the texture of ecclesiastical vestments, both in the West and East. It takes its name from being composed of four capital gammas (r) placed back to back, thus forming a voided Greek cross. The gammas were also sometimes placed face to face, so as to constitute a hollow square, in the centre of which cross was inscribed. Vestments so decorated, were known by the name of polystauria (πολυσταύρια). SEE FYLFOT.