偏差
piānchā · HSK 7
error
🎯 偏 lean/slant + 差 difference = a slanted difference = deviation
偏 means to lean or be off to one side, and 差 means difference or discrepancy. Put together, a sideways or off-to-one-side difference is exactly a deviation or error from the expected value.
偏 — person radical 亻 + 扁 (flat/biǎn)
A semantic-phonetic compound: 亻 (person) gives the meaning side, while 扁 supplies the sound. Originally suggesting a person standing off to one side, it came to mean 'slanted,' 'inclined,' or 'one-sided,' and by extension 'biased' or 'partial.'
差 — 垂 (drooping) + 工 (work/tool)
Originally depicted a hand reaching down to grasp grain stalks of uneven length, suggesting discrepancy or unevenness. From this came the meaning 'difference' or 'to differ.' The reading chā specifically carries the sense of disparity, while other readings developed meanings like 'to dispatch' (chāi) and 'poor/lacking' (chà).