Dic: stiletto (wikipedia)

A stiletto is a knife or dagger with a long slender blade and needle-like point, primarily intended as a stabbing weapon.[1][2] The stiletto blade's narrow cross-section and acuminated tip reduces friction upon entry, allowing the blade to penetrate deeply.[1][3] Some consider the stiletto a form of dagger, but most stilettos are specialized thrusting weapons not designed for cutting or slashing, even with edged examples.[1][4] 

Over time, the term stiletto has been used as a general descriptive term for a variety of knife blades exhibiting a narrow blade with minimal cutting surfaces and a needle-like point, such as the U.S. V-42 Stiletto, while in American English usage, the name stiletto can also refer to a switchblade knife with a stiletto- or bayonet-type blade design.[5] The term is also used interchangeably with stiletto heel, a long, thin, high heel for certain boots and shoes, usually for women. (... ...)

..... http://en.wikipedia.org/wiki/Stiletto