1. a fastening device with a frame and movable pin, used to secure belts, straps, or shoes

1. to fasten or secure with a buckle
2. to bend, warp, or collapse under pressure or stress
3. to apply oneself with determination
Usage: often used with ‘down’

Examples

• She adjusted the buckle on her leather belt.
• The silver buckle on his shoe was tarnished.
• Please buckle your seatbelt before we start driving.
• The metal beam began to buckle under the weight.
• The pavement buckled in the extreme heat.
• He decided to buckle down and study for his exams.
• The bridge buckled during the earthquake.
• Make sure to buckle the straps tightly.