buckle

buckle

I

buck‧le¹ /ˈbʌkəl/ verb
1.  BEND  [intransitive and transitive] to become bent or curved because of heat or pressure, or to make something bend or curve in this way:
    The steel pillars began to buckle.
    buckle under
    The rails buckled under the intense heat of the fire.
2.  KNEES/LEGS  [intransitive] if your knees or legs buckle, they become weak and bend
   SYN  give way:
    John felt his knees start to buckle.
3.  DO SOMETHING YOU DO NOT WANT  [intransitive] to do something that you do not want to do because a difficult situation forces you to do it
   SYN  give in:
    He refused to buckle.
    buckle under the pressure/strain/weight
    A weaker person would have buckled under the weight of criticism.
4.  FASTEN  [intransitive and transitive] to fasten a buckle, or be fastened with a buckle:
    Amy buckled the belt around her waist.
    buckle something on/up/together
    Lou was buckling on his revolver.
     
buckle down phrasal verb
  to start working very hard
    buckle down to
    You’d better buckle down to some revision now.
buckle up phrasal verb
  to fasten your seat belt in a car, aircraft etc

II

buckle² noun [countable]a piece of metal used for fastening the two ends of a belt, for fastening a shoe, bag etc, or for decoration