Silk glands are specialized organs found in spiders and certain insects, which produce the silk used for spinning webs, cocoons, and other structures. Some synonyms for silk gland include spinneret, spinnerette, and silk duct. The spinneret or spinnerette is the external opening of the silk gland through which the silk is extruded in fine threads. In addition to the spinneret, some insects have specialized structures called silk ducts that lead from the silk gland to the spinneret. Other synonyms may include silk organ, silk-producing organ, and silk-secreting gland. The silk produced by these glands is a remarkable material with many uses and applications in textiles, medicine, and industry.