1. A filament from the cocoon of the silkworm called a have. It is composed of a bifilar (two-filament) substance: fibroin gummed together with sericin, a gum. It is protein.
  2. Thread or fabric made from same. Almost all commercial silk is made from cocoons spun by silkworms of the genus Bombyx.
  3. Four commercial varieties of silk: Mulberry silk, Tussar (Tussar) silk, Eri silk and Muga silk. (Only in India are all four commercial varieties produced.) Silk is an animal fibre.