細絲 [细丝]

Jyutping sai3 si1
Pinyin xì sī

Definitions (Wiktionary)
  1. noun
    fine silk
  2. noun, Cantonese, obsolete
    Synonym of 元寶／元宝 (yuánbǎo, “a sycee, an ancient Chinese gold or silver ingot”).
    (syn.) 元宝, 元寶