The concept of getting hit (or hitting someone) with flying debris is so well-known now that many don't realize that it had to be invented. Or that it was named after its inventor.
Although we may not realize that objects like the leotard or the venn diagram are named for their creators, the concept isn't too weird. At least we knew that they were inventions. One incredibly effective war tactic has become so common that most people don't realize that it had to be invented. When we say that people were hit with shrapnel, we may think of it as incidental to an explosion or integral to it. We don't think of it as something that can be registered for a patent.
Henry Shrapnel was about twenty-three years old when he came up with the concept of shrapnel in 1784. Fragmenting weapons were already in use, and being in the British army, he would have been well aware of them. People would stuff a case with bits of metal and watch it explode towards the enemy as it left the barrel of the weapon. They'd also just fire pellets directly from a weapon. Shrapnel came up with something a little more focused. He made a case, and filled it with pellets, but added a fuse so it could be fired whole towards the enemy troops and explode when it reached them. Different sized cases and interior pellets could be used to kill humans, horses, or to destroy equipment.
The concept wasn't put into active use until 1804, but Shrapnel was credited with the technological advance and awarded a generous yearly stipend for life. Over the years the term "shrapnel" has drifted from use in one particular type of shell to the fragments sent off by any kind of explosion. Whether he'd enjoy the credit he now has is debatable.