These words all describe sharpened or pointed instruments commonly set in handles. Knife is the general term for any instrument used for cutting, piercing or spreading, with one or more sharpened edges, and sometimes with pointed blades. A knife , though it may be used as a weapon, is no more essentially a weapon than is a paperweight or a pair of shears, which can also be formidable weapons. For a knife used as a weapon, American criminals have long had a word, variously spelt but now generally rendered shiv . In modern criminal slang it may refer to a switchblade knife , but the connection is not inevitable. Should switchblade knives be replaced by other, perhaps more ingeniously concealed knives , shiv may well make the transition as effortlessly as it has many times in the past.

A dagger , unlike a knife , is made to be used as a weapon. Daggers are any sharp, pointed and edged weapons for stabbing. The printing mark (†) expresses fairly well the common shape daggers . All the other terms here considered are specific kinds of daggers.

A dirk is a Highland Scottish dagger , rather long, with a straight blade. A poniard is a small dagger , especially one with a triangular or four-sided blade. A stiletto is a small dagger with a narrow blade that is comparatively thick in cross section. Misericord (or misericorde ) describes a dagger used in the Middle Ages to give the coup de grace , or death blow, to fallen knights.