Threads of congealed worm spit. Mmmmm. Silk definitely sounds better.
I can see the scenario, way back in ancient China,

»So we've got this stuff, it's like thread, and you can weave it into cloth that feels great against your skin. It's lightweight, but very warm. It's like nothing else, really.«

»So what do you call it?«

»Congealed worm spit.«

»Uh-huh. We'll let the boys in marketing work on the name. Sign here.«