Actually I believe that traditionally, the skean dubh would have been entirely concealed in the stocking. As told in the familiar lore of Scotland, or as I was told, these hidden knives came about with the Scottish practice of always being well armed even in the most everyday situations. It was customary however to put down your arms in visits or meeting situations as a sign of truce or peaceful interaction.
That was until the fateful events at Glencoe, when clansmen in a weeklong visit and trustingly disarmed, were cruelly massacred by their hosts in a well planned and deceitful act.
After this, while giving up the bulk of his arms, the clansman kept a sort of back up weapon in his stocking, the small but deadly knife, skean dubh,
In Gaelic, the term skean =knife and dubh, has often been taken to mean black.
However in its more common simile, it actually means 'dark' or more directly, hidden. Therefore it is a 'hidden' knife.
By the same token, in Gaelic, the famed "Black Watch" regiment actually began as a covert 'undercover' unit used by the British to patrol Highland regions and maintain control. Therefore the eventual sobriquet for the regiment when formalized was not for black or somber toned apparel but the 'hidden' purpose of its formation.
In my own surname, in Gaelic, MacDhubghaill, means, son of the 'dark' foreigner, therefore unclear origins
or so family lore goes .
Norman.....we crossed posts!!!!
I remain curious on the 'jimping' or notching along the blade at the back, often I think on dirks as well. I think this was for the utility purposes in many cases....scaling fish?