Gouache is a heavy, opaque watercolor paint, sometimes called body color, producing a less wet-appearing and more strongly colored picture than ordinary watercolor. Also, any painting produced with gouache.
Filigree is a delicate, lacelike, intricate ornamentation, usually made from thin wire. In this case, gold is intricately painted over the gouache to enhance the distinctly Mid-East style of Ivonne Baki's paintings (see close-up below).