*Torsion* is twisting — specifically, what happens inside a solid thing when one end is turned one way and the other end is held still or turned the other way. Take a metal bar, grip both ends, and twist: the bar is now under torsion. Engineers use the word for that stress, and they can measure it: a drive shaft in a car, a bridge deck in a strong side wind, and the wing of an aeroplane all have to be built to survive torsion.

*Torsion*torsion is twisting就是扭轉 — specifically, what happens inside a solid thing when one end is turned one way and the other end is held still or turned the other way.——具體來說，是一個固實的東西，一端往一個方向轉、另一端固定不動或往反方向轉時，內部發生的狀況。 Take a metal bar, grip both ends, and twist拿一根金屬棒，抓住兩端扭 : the bar is now under torsion.：這根棒子現在就處於torsion扭轉的狀態。 Engineers use the word for that stress工程師用這個字來講那種應力, and they can measure it，而且是可以測量的 : a drive shaft in a car, a bridge deck in a strong side wind, and the wing of an aeroplane all have to be built to survive torsion.：汽車的傳動軸、強側風下的橋面，還有飛機的機翼，都必須造得能承受torsion。

The *torsion bar* is the piece of everyday machinery students are most likely to meet. It is a straight steel bar used as a spring in a car's suspension: instead of coiling like a normal spring, it takes the bump by twisting along its length and then untwisting. Tanks and many older cars used them.

The *torsion bar*torsion bar扭力桿 is the piece of everyday machinery students are most likely to meet.是學生最可能在日常機械裡遇到的東西。 It is a straight steel bar used as a spring in a car's suspension它是一根用在汽車懸吊系統裡當彈簧用的直鋼棒 : instead of coiling like a normal spring, it takes the bump by twisting along its length and then untwisting.：它不像一般彈簧那樣捲成圈，而是靠著整根棒子扭轉、再回彈來吸收顛簸。 Tanks and many older cars used them.坦克和很多老車都用過這種東西。

It is a technical word, and I would keep it that way. In ordinary conversation English says *twist* or *twisting*. Nobody complains that the wire has torsion in it; they say it got twisted.

It is a technical word這是個很技術性的字, and I would keep it that way.，我會建議就讓它保持技術性就好。 In ordinary conversation English says *twist* or *twisting*.日常對話裡，英文會說twist或twisting。 Nobody complains that the wire has torsion in it沒有人會抱怨說電線有torsion; they say it got twisted.；他們會說它扭到了got twisted。

Two other places it turns up, worth knowing because they surprise people. In medicine, *testicular torsion* and *ovarian torsion* are serious emergencies where an organ twists on its own blood supply and cuts off the blood — this is a real, common use in hospitals.

Two other places it turns up還有兩個地方會出現這個字, worth knowing because they surprise people.，值得知道，因為會讓人意外。 In medicine在醫學上, *testicular torsion* and *ovarian torsion* are serious emergencies，testicular torsion睪丸扭轉和ovarian torsion卵巢扭轉是很嚴重的急症 where an organ twists on its own blood supply and cuts off the blood，指器官纏住自己的血管，把血流切斷 — this is a real, common use in hospitals.——這是醫院裡真實而常見的用法。

And in mathematics, torsion has a precise meaning in geometry and in group theory that has drifted a long way from twisting metal; if a student meets it in a maths book, they should not expect this everyday sense to help them.

And in mathematics而在數學裡, torsion has a precise meaning in geometry and in group theory that has drifted a long way from twisting metal，torsion在幾何學和群論裡有精確的意思，已經跟扭金屬差了十萬八千里; if a student meets it in a maths book, they should not expect this everyday sense to help them.；如果學生在數學課本裡遇到這個字，不要期待日常的這個意思能幫上忙。

The dictionary sometimes lists a verb *to torsion*, but I would tell students plainly: it is very rare and sounds wrong to most ears. Use *twist*.

The dictionary sometimes lists a verb *to torsion*字典裡有時候會列出動詞to torsion, but I would tell students plainly，但我會直接跟學生說 : it is very rare and sounds wrong to most ears.：這個用法非常少見，大部分人聽起來會覺得怪怪的。 Use *twist*.請用twist就好。