曲线
qū xiàn · HSK 7
curved line
〰️ 曲线 = 曲 bent/crooked + 线 line/thread = a bent line, a curve
曲 means bent or winding (also a song/tune), and 线 is line or thread. Together a bent line is a curve. The same bent sense gives the figurative reading: roundabout or indirect rather than straight.
曲 — pictograph of a bent carpenter's tool or curved object
曲 is a pictograph showing a bent or curved shape, originally depicting a carpenter's measuring tool or a curved frame. From this concrete image of bending came the abstract senses of 'crooked,' 'wrong,' and 'tune/melody' (since songs follow winding contours). The reading qū carries the bending senses, while qǔ means 'song.'
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.