A road, path, or railway that climbs a steep hill by turning back on itself again and again — up a bit, sharp bend, back the other way, sharp bend, up a bit more. Seen from above it looks like a zigzag.

A road, path, or railway一條道路、小路或鐵路 that climbs a steep hill爬陡坡 by turning back on itself again and again會一次又一次自己往回轉──up a bit往上一點，sharp bend急轉彎，back the other way往另一邊回去，sharp bend再急轉彎，up a bit more再往上一點。Seen from above從上面看，it looks like a zigzag就像鋸齒形。

Mountain roads are built this way because a straight road up a steep slope would be too steep to drive or walk. In American English this is the everyday word, and it is very common in hiking: "the trail has twelve switchbacks before the top". It works as a verb too — "the road switchbacks up the valley".

Mountain roads are built this way山路會這樣蓋 because a straight road up a steep slope would be too steep to drive or walk因為直接爬陡坡的直路會太陡，沒辦法開車或走路。In American English在美式英語裡 this is the everyday word這是日常用字，and it is very common in hiking在登山時很常見："the trail has twelve switchbacks before the top"意思是「這條步道到山頂前有十二個之字彎」。It works as a verb too它也可以當動詞用──"the road switchbacks up the valley"意思是「這條路沿著山谷之字形往上爬」。

In British English it has an older second life: a switchback was a fairground ride that ran up and down steep slopes — what we would now call a roller coaster. From that comes the figurative use: "a switchback year", "the switchback of the past few months" — meaning up, down, up, down, with no rest. That figurative use is much more common in Britain than in America.

In British English在英式英語裡 it has an older second life它還有個較舊的第二個意思：a switchback was a fairground ride從前switchback是一種遊樂園設施 that ran up and down steep slopes會在陡坡上下衝 — what we would now call a roller coaster也就是我們現在說的雲霄飛車。From that comes the figurative use由此而來的是比喻用法："a switchback year", "the switchback of the past few months"這類說法 meaning up, down, up, down, with no rest意思是上、下、上、下，沒有休息的時候。That figurative use這種比喻用法 is much more common in Britain than in America在英國比在美國常見得多。

The name comes from railways, where a switch turns a train from one track onto another. A train that could not climb straight up would go forward, stop, be switched, and reverse up the next stretch — switch, back, switch, back.

The name comes from railways這個名字來自鐵路，where a switch turns a train from one track onto another在那裡switch（轉轍器）把火車從一條軌道轉到另一條軌道。A train that could not climb straight up沒辦法直接往上爬的火車 would go forward就會往前開，stop停下來，be switched被轉轍，and reverse up the next stretch然後倒退著爬上下一段──switch, back, switch, back也就是switch（轉），back（退），一直重複。