Bell or sweet peppers and chili peppers are actually from the same family of plants (same as the tomato, in fact!). They were first discovered by the Western world when Columbus travelled to America. At that time, peppercorns were a very prized condiment, so he called these vegetables “peppers”.
The main difference between bell peppers and chili peppers is the spiciness. The spiciness of peppers is measured by using Scoville’s method. This involves extracting the pepper’s spiciness through heat and measuring it on a scale.
Bell peppers measure 0 on the Scolville scale. Chili peppers measure 100. The hottest pepper? The Habanero, which clocks in at 100,000 on the Scolville scale.