silk·worm / ˈsilkˌwərm/ • n. the commercially bred caterpillar of the domesticated silkworm moth (Bombyx mori), which spins a silk cocoon that is processed to yield silk fiber. ∎  a commercial silk-yielding caterpillar of a saturniid moth. See tussore, tussore moth.

silkworm Moth caterpillar that feeds chiefly on mulberry leaves. The common domesticated Bombyx mori is raised commercially for its silk cocoon. Length: 7.5 cm (3in). Family Bombycidae.