|1.||a clasp for fastening together two loose ends, esp of a belt or strap, usually consisting of a frame with an attached movable prong|
|2.||an ornamental representation of a buckle, as on a shoe|
|3.||a kink, bulge, or other distortion: a buckle in a railway track|
|4.||to fasten or be fastened with a buckle|
|5.||to bend or cause to bend out of shape, esp as a result of pressure or heat|
|[C14: from Old French bocle, from Latin buccula a little cheek, hence, cheek strap of a helmet, from bucca cheek]|
Fasten a seat belt, as in All the children must learn to buckle up as soon as they get in a car. This term came into wide use in the second half of the 1900s, when seat belts became mandatory automobile equipment. Earlier they had been used mainly in airplanes.