An ear dagger is a relatively rare and exotic form of dagger that was used during the late Middle Ages and Renaissance. It is so named because the pommel of the dagger has a very distinctive shape, somewhat resembling a human ear. Ear daggers frequently have a single sharpened edge that ends in an acute point.
It is thought that the ear dagger was introduced to Europe from Spain, where it presumably originated from the Moors.
"In the 14th century an interesting version of the rondel appeared. This was the eared dagger, which shares its heritage with the blade known to the Turks as the yataghan and to the Cossacks as the shashqa. The pommel of eared daggers was split in two to allow the thumb to be hooked over the pommel to impart greater force to the stabbing blow. Curiously, despite its (odd) appearance, the eared dagger became widely associated with royalty and was also a favorite weapon of assassins in Italy during the 15th and 16th centuries."
- "Ear Dagger ~ historical blade by Hanford Miller". bladeforums.com.
- myarmoury.com article on rondel daggers, with an illustration of an ear dagger