styletPronunciation: /ˈstʌɪlɪt/Definition of stylet noun 1 Medicine a slender probe. a wire or piece of plastic run through a catheter or cannula in order to stiffen it or to clear it. 2 Zoology (in an invertebrate) a small style, especially a piercing mouthpart of an insect. Origin: late 17th century: from French stilet, from Italian stiletto (see stiletto)stylet in other Oxford dictionaries Definition of stylet in the US English dictionary