What the heck is a Sgain Dubh? (Sounds like "skean doo")

A Sgain Dubh is a small, singled-edged knife (Gaelic sgian) worn as part of traditional Scottish Highland dress along with the kilt. It is worn tucked into the top of the kilt hose with only the upper portion of the hilt visible. The sgian-dubh is normally worn on the right leg, but can also be worn on the left, depending on whether the wearer is right or left-handed. The sgian-dubh may have evolved from the sgian-achlais, a dagger that could be concealed under the armpit. Used by the Scots of the 17th and 18th centuries, this knife was slightly larger than the average modern sgian-dubh and was carried in the upper sleeve or lining of the body of the jacket.