I’ve also heard them called shanks, the word itself, “shiv” or “shank,” intuitively sounds like their intended use, further relayed with these photos from this article by William Drenttel in Design Observer:
A shiv is a weapon crafted from the limited resources of a prisoner’s closed world. Crudely constructed from such things as spoons, shoelaces and upholstery tacks, shivs lie somewhere between the graceful and the grotesque. They’re primitive, too — like outsider art, but produced deep on the inside.
The individual parts that make up a shiv tend to be everyday objects, innocent things furtively reconstituted as lethal weapons. Each design choice is essential, but what’s particularly notable is that shivs, at their core, are not so much evocations of minimalism as they are symbols of survivalism. A shiv is all about masked utility: it’s an innocuous object with improbably toxic intent (whether used to attack others or to protect oneself…)
Read More: Design Observer: