The term was spelled dork or dirk during the 17th century,[4] presumed related to the Danish, Dutch and Swedish dolk, and the German dolch, tolch; from a West Slavic Tillich.
The dirk became symbolic of a Highland man’s honour and oaths were sworn on the steel which was believed to be holy.
The English, aware of this, used the custom against the Highlanders after Culloden: When Highland dress was prohibited in 1747 those Gael who could not read or sign an oath were required to swear a verbal oath, "in the Irish (Scots Gaelic) tongue and upon the holy iron of their dirks", not to possess any gun, sword, or pistol, or to use tartan: "... and if I do so may I be cursed in my undertakings, family and property, may I be killed in battle as a coward, and lie without burial in a strange land, far from the graves of my forefathers and kindred; may all this come across me if I break my oath.
"During the period of proscription, only service in a British regiment permitted Highlanders to bear their traditional arms and dress.
[13] Many Scottish dirks carry a smaller knife and fork which fit into compartments on the front of the sheath,[14] and a smaller knife known as a sgian dubh is also worn tucked into the top of the hose when wearing a kilt.
[2] In the Royal Navy, the naval dirk is still presented to junior officers; the basic design of the weapon has changed little in the last 500 years.
[2] The naval dirk (Polish: kordzik, Russian: кортик) became part of the uniform of naval officers and civilian officials in the Navy Ministry of the Russian Empire, and in the Soviet navy an element of the dress uniform of officers.