Read the dictionary definition of buckle. All definitions for this word.
1. fastener that fastens together two ends of a belt or strap; often has loose prong
2. a shape distorted by twisting or folding
3. bend out of shape, as under pressure or from heat
1. The highway buckled during the heat wave
4. fold or collapse
1. His knees buckled
5. fasten with a buckle or buckles