silk thread; silk yarn
Refers to thread or yarn produced from silkworm cocoons, used in textiles and sericulture.
蚕糸は絹織物の原料です。
Silk thread is the raw material for silk fabrics.
この地域
This region has produced silk thread since long ago.
Silk yarn production is thriving in this region.
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.