界线
jiè xiàn · HSK 7
limit
🚧 界 boundary + 线 line = the dividing line that marks the limits
界 means boundary or realm; 线 means line or thread. Put them together and you get the boundary-line: the limits or bounds where one zone ends and the next begins.
界 — field 田 + scope 介
界 combines 田 (field) as the semantic component with 介 (jiè) as the phonetic. The original sense referred to boundaries between fields, then broadened to any border, limit, or realm — yielding modern meanings like 'world' (世界) and 'boundary' (边界).
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.