 The spear point is one of the stronger blade point designs in terms of penetration stress, and is found on many thrusting knives such as the dagger.The term spear point is occasionally and confusingly used to describe small single-edged blades without a central spine, such as that of the "pen knife", a small folding-blade pocket knife formerly used in sharpening quills for writing.Pen-knife may also nowadays refer to a knifelike weapon blade pattern of some of larger pocket knife blades that would otherwise be termed drop-point designs.