What is sgian dukh?

n. Pronounced (skee' in dhu) or (skeen dhu). A small knife of Scottish origin. Usually had an exceptionally sharp 2-3 inch blade on a handle of similar length. Typical 3rd weapon of Scottish warriors, after the claymore and dirk.

Often misspelled: skian dhu, skeen du, sgian duh, skeen dhuk, etc.