Merriam-Webster Collegiate Dictionary - stylet

 noun  Etymology: French, from Middle French stilet stiletto, from Old Italian stiletto — more at stiletto  Date: 1697  1.  a. a slender surgical probe  b. a thin wire inserted into a catheter to maintain rigidity or into a hollow needle to maintain patency  c. a pointed instrument (as for graving)  2. a relatively rigid elongated organ or appendage (as a piercing mouthpart) of an animal  3. stiletto