A small dagger worn in the sock by Scotsmen is called a "Sgian Dhubh" which is pronounced as if it were spelled SKI-UN-DOO. Nowadays it is mostly decorative but in days now long past is was a backup concealed weapon that was carried for when a man would normally park his main weapons (as when entering a friends home) just in case his "friend" was no longer trustworthy. politics being what they are.
A small dagger is a stiletto.
dirk
kaiken
Poniard
Katropis, looking glass.
Pesh kabz Phurba Punyal
poignard or poniard
derk Sgian dhu
A Dagger Board is a small removable board that acts as a Keel on a small sailboat.
STILETTO The actual answer begins with P and the word is poniard
The name of the Roman dagger was pugio.
a small killing knife