buckle
noun [ C ] uk/ˈbʌk.əl/ us/ˈbʌk.əl/
（皮带等的）搭扣，扣环
a piece of metal at one end of a belt or strap, used to fasten the two ends together
buckle
verb uk/ˈbʌk.əl/ us/ˈbʌk.əl/
(FASTEN)
[ T or I ]用扣环扣住
to fasten or be fastened with a buckle
(BEND)
[ T or I ]弯曲;变形
to bend something or become bent, often as a result of force, heat, or weakness
The intense heat from the fire had caused the factory roof to buckle. 大火的高温烤得工厂的屋顶变了形。
Both wheels on the bicycle had been badly buckled. 自行车的两个车轮都已严重变形。
I felt faint and my knees began to buckle. 我感到眩晕，腿也站不直了。
(BE DEFEATED)
buckle under something 屈服于（困境）
to be defeated by a difficult situation
But these were difficult times and a lesser man would have buckled under the strain. 但当时是困难时期，脆弱的人肯定会被压力压垮。
Phrasal verbs
buckle down 开始努力工作
to start working hard
He'll have to buckle down (to his work) soon if he wants to pass his finals. 如果他想通过期末考试就必须马上下苦功。
buckle up US informal (UK belt up)系紧安全带
to fasten the belt that keeps you in your seat in a car or a plane
Don't forget, buckle up before you start driving. 别忘了开车前系好安全带。