Chiles all belong to the Solanaceae (nightshade) family, the same one as tomatoes, eggplant and tobacco. While they are called chiles in Mexico, they are known as ajíes in Peru, Chile, Colombia and Venezuela; pimentas in Brazil; and peppers or chile peppers in the United States.
Today there are five species of the genus Capsicum—annum, baccatum, frutescens, pubescens and chinense, though this may change due to more genetic research.