What term describes an intricate pattern or design?

The term that describes an intricate pattern or design is "Arabesque." This word originates from the style of ornamentation found in Islamic art, which features complex and interwoven patterns often inclusive of floral and geometric motifs. Arabesques are characterized by their elaborate, decorative quality, which can be seen in architecture, textiles, and illustrations.

While other terms in the question refer to different concepts, "Jamboree" typically denotes a large celebration or gathering, often associated with scouting activities. "Chiaroscuro" relates to the use of strong contrasts between light and dark in art, usually to create a sense of volume in modeling three-dimensional objects and figures. Lastly, "Foliage" refers to plant leaves collectively, and does not pertain to a structured design but to the greenery present in nature. Therefore, Arabesque stands out as the correct choice due to its specific association with intricate patterns and designs.