线索
xiànsuǒ · HSK 5
lead
🧵 线 = thread + 索 = rope/search; a thread you follow to search out a lead
线 is the literal thread or line; 索 means rope or to search for. Together: the thread-you-search-along, i.e. a clue or lead. Detectives follow 线索 the way you'd trace a string back to its source.
线 — silk radical 纟 + 戋 (jiān, phonetic)
线 is a semantic-phonetic compound. The silk radical 纟 signals the meaning 'thread' or 'string,' while 戋 hints at the sound. Originally referring to silk thread, its meaning broadened to any thin line, wire, or route. The traditional form is 線.