底线
dǐ xiàn · HSK 7
bottom line
📏 底 (bottom) + 线 (line) = the bottom line
底 means bottom or base, 线 means line or thread. Together they give you the literal bottom line — the baseline you cannot cross, whether in negotiations, sports courts, or underlining text.
底 — 广 (shelter radical) + 氐 (phonetic 'dǐ')
底 is a semantic-phonetic compound. The 广 radical depicts a roofed structure or shelter, suggesting the bottom or base of a building. The component 氐 supplies the sound 'dǐ' and originally meant 'low' or 'base,' reinforcing the meaning. Together they convey 'bottom,' 'foundation,' or 'underneath.'
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.