silk thread; silk yarn
Refers to thread or yarn produced from silkworm cocoons, used in textiles and sericulture.
Silk thread is the raw material for silk fabrics.
Silk yarn production is thriving in this region.
This region has produced silk thread since long ago.
The craftsman is carefully spinning the silk thread.
生糸 refers specifically to raw, unprocessed silk thread straight from the cocoon, whereas 蚕糸 is a broader term covering silk thread in general, including after some processing.
Compound of 蚕 (silkworm) and 糸 (thread). The reading さんし is the on'yomi of both characters.