A single silkworm cocoon contains up to a kilometer of silk thread — China guarded this secret for millennia until monks smuggled eggs out in hollow bamboo canes.
The silky protective case spun by the larvae of moths and other insects as a shelter during the pupal stage. Figuratively, a warm, safe, protective covering or environment.
From French cocon (cocoon, eggshell), from Provençal coucoun, diminutive of coco (shell, eggshell), ultimately from Latin coccum (berry, kermes grain) or from a nursery word for egg/shell Key roots: coco (Provençal: "shell, eggshell"), coccum (Latin: "berry, grain (possibly related)").
A single silkworm cocoon contains approximately 300–900 meters of continuous silk filament — up to nearly a kilometer of thread from one tiny larval case. The Chinese silk industry, which kept silkworm cultivation (sericulture) a closely guarded secret for thousands of years, was built entirely on the cocoon of Bombyx mori. According to legend, the secret was smuggled out of China around 550 CE by two Nestorian monks who hid silkworm eggs