The term ART ___ (RETRO DESIGN STYLE) is completed by the word DECO, a four-letter word. Deco is short for Art Deco, a style of visual arts, architecture and design that first appeared in France just before World War I. It is characterized by bold geometric shapes, bright colors, and lavish ornamentation. Art Deco was popularized in the 1920s and 1930s and has since become a classic design style.