The buckle or clasp is a device used for fastening two loose ends, with one end attached to it and the other held by a catch in a secure but adjustable manner. Often taken for granted, the invention of the buckle was indispensable in securing two ends before the invention of the zipper. The basic buckle frame comes in a variety of shapes and sizes depending on the intended use and fashion of the era. Buckles are as much in use today as they have been in the past: used for much more than just securing ones belt, instead they are one of the most dependable devices in securing a range of items.

The word "buckle" enters Middle English via Old French and the Latin buccula or "cheek-strap," as for a helmet. Some of the earliest buckles known are those used by Roman soldiers to strap their body armor together and prominently on the balteus and cingulum. Made out of bronze and expensive, these buckles were purely functional for their strength and durability vital to the individual soldier. The baldric was a later belt worn diagonally over the right shoulder down to the waist at the left carrying the sword, and its buckle therefore was as important as that on a Roman soldier’s armor.

The buckle essentially consists of four main components: the frame, chape, bar, and prong. The oldest Roman buckles are of a simple "D"-shaped frame, in which the prong or tongue extends from one side to the other. In the 14th century, buckles with a double-loop or "8"-shaped frame emerged. The prongs of these buckles attach to the center post. The appearance of multi-part buckles with chapes and removable pins, which were commonly found on shoes, occurred in the 17th century. Buckle showing various components:

The frame is the most visible part of the buckle and holds the other parts of the buckle together. Buckle frames come in various shapes, sizes, and decorations.

Chapes or "caps" of various designs could be fitted to the bar to enable one strap end to be secured before fastening the other, adjustable end. This made buckles easily removable and interchangeable, leading to a significant advantage since buckles were expensive.

The prong (also named pin) is typically made out of steel or other types of metal. In conventional belts, the prong fits through the buckle to secure the material at a pre-set length.

The bar served to hold the chape and prong to the frame. When prongs and chapes are removed from the buckle design, the buckle incorporated a movable bar relying on the tension of the adjusted belt to keep it in place.

Although any device that serves to secure two loose ends is casually called a buckle, if it consists of two separate pieces with one for a hook and the other for a loop, it should be called a clasp. Clasps became increasingly popular at the turn of the 19th century with one clear disadvantage: since each belt end was fixed to each clasp piece, the size of the belt was typically not adjustable unless an elastic panel was inserted.

A buckle without a chape or prongs is called a buckle trim or slide.

A conventional snap-fit buckle that is formed by a "male" buckle member—the hook end—and a "female" buckle member—the insertion end. This sort of buckle may be found connecting many strapped items such as pet harnesses, safety harnesses, personal flotation jackets, fanny packs and other bags, belts, gun slings, and boots. It is also known as the "parachute buckle".

六级/考研单词: buckle, clasp, fasten, seldom, indispensable, vogue, era, helmet, strap, armour, prominent, bronze, expense, durable, waist, sword, thereby, component, pin, tense, casual, loop, elastic, insert, trim, pet, harness, parcel, parachute