—n.
1 a flat often rectangular frame with a hinged pin, used for joining the ends of a belt, strap, etc.
2 a similarly shaped ornament, esp. on a shoe.
—v.
1 tr. (often foll. by up, on, etc.) fasten with a buckle.
2 tr. & intr. (often foll. by up) give way or cause to give way under longitudinal pressure; crumple up.
Phrases and idioms:
buckle down make a determined effort. buckle to (or down to) prepare for, set about (work etc.). buckle to get to work, make a vigorous start.
Etymology: ME f. OF boucle f. L buccula cheek-strap of a helmet f. bucca cheek: sense 2 of v. f. F boucler bulge
Useful english dictionary. 2012.