Festoon (from French feston, Italian festone, from a Late Latin festo, originally a festal garland, Latin festum, feast), a wreath or garland, and so in architecture a conventional arrangement of flowers, foliage or fruit bound together and suspended by ribbons, either from a decorated knot, or held in the mouths of lions, or suspended across the back of bulls heads as in the Temple of Vesta at Tivoli. The motif is sometimes known as a swag when depicting fabric or linen.
The design was largely employed both by the Ancient Greeks and Romans and formed the principal decoration of altars, friezes and panels. The ends of the ribbons are sometimes formed into bows or twisted curves; when in addition a group of foliage or flowers is suspended, it is called a drop or margent.
Its origin is probably due to the representation in stone of the garlands of natural flowers, etc., which were hung up over an entrance doorway on fête days, or suspended round the altar.