A penknife, or pen knife, is a British English term for a pen that looks like a knife. One popular folk etymology makes an association between the size of a penknife and a small ballpoint pen, however the phrase “penknife” is much older. Originally, penknives were used for thinning and pointing quills to prepare them for use as dip pens and, later, for repairing or re-pointing the nib. They did not necessarily have folding blades, but resembled a scalpel or wood knife by having a short, fixed blade at the end of a long handle. Today the word penknife is the common British English term for both a pocketknife, which can have single or multiple blades, and for multi-tools, with additional tools incorporated into the design.
Over the last hundred years there has been a proliferation of multi-function knives with assorted blades and gadgets, including; awls, reamers, scissors, nail files, corkscrews, tweezers, toothpicks, and so on. The tradition continues with the incorporation of modern devices such as ballpoint pens, LED torches, and USB flash drives. The most famous example of a multi-function penknife is the Swiss Army knife, some versions of which number dozens of functions and are really more of a folding multi-tool, incorporating a blade or two, than a penknife with extras. A larger folding knife, especially one in which the blade locks into place, is often called a claspknife.