Those long, thin, slightly curling red peppers you see in farmers markets and at the grocery store are most commonly known as cayenne peppers. One of the spiciest peppers, cayenne is the most common name, but the pepper is known by a variety of other monikers, depending on historical era, geographic region, and, on occasion, marketing. You can use cayenne in a variety of dishes, but traditionally it is part of Mexican, Caribbean and South American cuisines.
In the mid-1600s, Nicholas Culpeper used the term guinea pepper for cayenne peppers. This name was originally a misnomer for guinea pepper, a reference to the West Indian history and origins of the cayenne pepper. Not very commonly used these days, this name is a little known piece of history associated with the cayenne pepper.
All plants have a scientific as well as a common name, which helps ensure that scientists or those involved in the scientific community can be certain they are all referring to the same thing. The scientific name for cayenne is Capsicum frutescens or Capsicum annum. Referring to cayenne as either one of these names is uncommon outside of the scientific community.
Cayenne is also sometimes called African bird pepper or just bird pepper. This is partly in reference to the warm climate and tropical growing regions where this pepper originates from, but it is also a reference to Thai bird chilies, which look similar to cayenne but are much smaller.
As one very spicy pepper, cayenne is usually referred to specifically, because it's best to warn folks before they ingest it. However, in some cases, cayenne is also just called capsicum, red pepper or chili pepper. These names can be misleading because they include a range of chili peppers and red peppers that aren't nearly as spicy as cayenne. Also, capsicum is the chemical in all peppers that gives them their spice content. More capsicum means more heat, but popular knowledge associates cayenne with being extra spicy, so it's frequently just referred to as capsicum.
Isabelle Hannigan has been a professional writer since 2004, with articles appearing in nationally distributed newspapers such as "The National Post." She is a registered dietitian and sports nutritionist, and has worked for the University of Guelph and Athlete's World. Hannigan holds a B.S. in biochemistry from McMaster University and an M.S. in nutritional sciences from the University of Guelph.