When cooking with other people, you sometimes have to stop and explain what you mean when you say "pepper." There's black pepper, ground from peppercorns, and then there's the various vegetables that originated in America: bell, banana, jalapeño, etc. Black pepper originated in Asia, so why do we call the other plants "peppers"? It was due to Christopher Columbus trying to find a new route to Asia. He didn't, but he still tried to make the best of it by bringing back spices to enrich King Ferdinand. A little misnaming would do.
Black pepper (Piper nigrum) had been a culinary mainstay of fine cuisine since the Roman Empire, beating out prior spicy compounds such as horseradish, mustard, and the arguably better long pepper. It was a valued addition to both food and medicine, yet getting it from Asia was expensive and difficult. Columbus was so eager to find pepper that he carried peppercorns with him. When he landed, he showed them to locals. They were similar enough to the allspice berries growing wild in Jamaica that Columbus also likened them to pepper: pimienta de Jamaica. Marjorie Shaffer writes in Pepper: A History of the World’s Most Influential Spice that Columbus was likely smart enough to know what he had wasn’t pepper, but that he probably didn’t care. Allspice and hot peppers headed for Europe.
Peppers from the New World were a hit, to the chagrin of Dutch spice traders. Read about the initial misnaming of peppers and how that affected world trade at Atlas Obscura.