A Claymore is a Scottish sword.
In 2268, Chief Engineer Montgomery Scott was dazzled by a Claymore when all the weapons in the Enterprise's armory were replaced by antique weaponry. (TOS: "Day of the Dove)
- Interestingly, Scotty was unaware that he was not looking at, nor holding, a Claymore sword. A possible explanation for this could be that the alien entity responsible for making Chekov believe he had a brother - when in fact he was an only child - also made Scotty see a Claymore where there wasn't one.