Chili peppers, also spelled chile or chilli, are varieties of the berry-fruit of plants from the genus Capsicum, which are members of the nightshade family Solanaceae, cultivated for their pungency. Chili peppers are widely used in many cuisines as a spice to add "heat" to dishes. Capsaicin and related compounds known as capsaicinoids are the substances that give chili peppers their intensity when ingested or applied topically. Chili peppers exhibit a range of heat and flavors. This diversity is the reason behind the availability of different types of paprika and chili powder, each offering its own taste and heat level.

Capsicum annuum is a fruiting plant from the family Solanaceae (nightshades), within the genus Capsicum which is native to the northern regions of South America and to southwestern North America. The plant produces berries of many colors including red, green, and yellow, often with pungent taste. It also has many varieties and common names including paprika, chili pepper, jalapeño, cayenne, bell pepper, and many more with over 200 variations within the species. It is also one of the oldest cultivated crops, with domestication dating back to around 6,000 years ago in regions of Mexico. The genus Capsicum has over 30 species but Capsicum annuum is the primary species in its genus, as it has been widely cultivated for human consumption for a substantial amount of time and has spread across the world. This species has many uses in culinary applications, medicine, self defense, and can even be ornamental.