The term “claymore” is used to describe two different types of weapons: a type of double-edged sword and an antipersonnel mine. Given that these two weapons were used in different eras and in different contexts, the type of claymore under discussion is usually obvious from the context of the conversation.
In the first sense, the claymore was a type of broadsword which was used historically in the Scottish Highlands. It has become closely associated with Scottish heritage and culture, due to the romanticization of the Highland Scots by the British and later generations of Scottish. This claymore was one among a family of weapons available to the Highland Scots, and it shared many characteristics with swords used in other regions of the world, suggesting that the basic design was universally useful.
A typical Scottish claymore was very heavy, with a long double edged blade. There were actually two versions of this sword; one had a hilt which was designed for two-handed use, and the other had a basket hilt, intended for one-handed use. Two-handed claymores were used through the 17th century, until they began to be supplanted by the one-handed basket hilt. Basket hilts carry a distinct advantage, since they protect the hand of the warrior; many one-handed claymores had hilts lined with velvet and other soft materials, and they were decorated with tassels and other ornaments on occasion as well.
The word “claymore” is derived from the Gaelic claidheamh, which means “sword.” A claidheamh mòr was a “great sword,” while a claidheamh de lamh was a “two handed sword.” Numerous examples of Scottish claymores can be seen in museums, and some are also included on military uniforms. Should you ever have an opportunity to wield a claymore yourself, you can see why the Highland Scottish warriors were famous, as the swords require immense strength and skill to be wielded effectively.
In the second sense, a claymore is a fragmentation mine which is designed to disable approaching enemy personnel. Claymores classically spit out ball bearings, although other types of shrapnel may be used as well. The mine was named for the Scottish sword by its inventor, who happened to be a Scot. Claymores can help to break up advancing enemy lines, and also as tools in ambushes; much like the Highland warriors of old, one does not generally want to encounter them with hostile intent.