For a variety of reasons, the carrying of blades is nearly ubiquitous in kilted fashion. This has probably a lot to do with connection to the violent militaristic past, or maybe that many conventions of Scottish dress were codified during the period of The Dress Act. Maybe it's because swords and daggers are just cool. In any case, it would be irresponsible of me not to say the following; bladed weapons aren't toys. They are sharp and hurt people. Also, they are regulated by law in many parts of the country. Waving them around can you arrested. Please exercise common sense.
A sgian dubh (scan dew) is a small single edged knife about two inches in length. The unsharpened side is notched. My understanding is that this was once used to scale fish. The handle is usually ebony with ornate silver furniture. Antler, bone, or natural hardwoods are also very popular. The name means "dark knife" or "hidden knife" as it was originally used as a weapon of last resort hidden on your person at all times. Nowadays it is most often used as utility knife, ice pick, or maybe to spread mayo. Knives are useful. Dark handled or officer's Sgain Dubhs are considered to be more formal. In recent years novelty sgain dubhs like the sgain brew bottle opener and other playful reinventions ave become more common. Multi-tools, sonic screwdrivers, carpenter pencils, tent stakes and waiters corkscrews have all been used in the place of the traditional sock knife.
The dirk is about twelve inches in length, and worn on the right side on a belt. It looks very much like the Sgain dubh but obviously quite larger. It bears some resemblance to a gladius or Roman sword. Like the Sgain dubh, they can be be quite ornate, and often functional. It can be worn with a Jacobite shirt, band uniform, Prince Charlie jacket, or regulation doublet.
The word "claymore" derives from the Gaelic meaning "great sword." Commonly it refers to one or two styles of sword.
The smaller of these is also sometimes referred to a Scottish broad sword, or back sword.(The back is the unsharpened side of the blade used for blocking.) More descriptively, it is known as the basket hilt claymore. In military dress uniforms, and ceremonial garb it takes the place of a gentlemen's saber.
The larger is the two handed claymore. Some of you
may quibble with my terminology, and insist that the sword to which I'm referring is called a "clay ga LA" (Sp?) Which translates to "two handed sword." Either term is acceptable provided of course that you are understood. It varies in length, but is usually around 45 inches in length. The most common design has cross guard is shaped like a Y with three or four circles on the ends. There are several variations, some of which are more historically accurate than others. It dates as far back _____, and was commonly used as against cavalry. Contrary to what you might expect it was actually much lighter than swords used in continental Europe at the time. It seems to me to be out of place in modern dress. The only exception I can of is in parades or costumed events such as a renn fest. Nonetheless, Pinterest tells me that it's fairly common place at weddings for kilted groomsmen to have claymores of either variety. I don't get it.