| silk [silk] GEOLOGY Microscopic needle-shaped crystalline inclusions of rutile in a natural gem from which subsurface reflections produce a whitish sheen resembling that of a silk fabric. INVERTEBRATE ZOOLOGY A continuous protein fiber consisting principally of fibroin and secreted by various insects and arachnids, especially the silkworm, for use in spinning cocoons, webs, egg cases, and other structures. TEXTILES A thread or fabric made from silk secretions of the silkworm. |