Basil, Thai basil, or sweet basil, is a common name for the culinary herb Ocimum basilicum of the family Lamiaceae (mints).It is a half-hardy annual plant, best known as a culinary herb prominently featured in Italian cuisine, and also plays a major role in Southeast Asian cuisines of Indonesia, Thailand, Vietnam, Cambodia, Laos, and the cuisine of Taiwan. Depending on the species and cultivar, the leaves may taste somewhat like anise, with a strong, pungent, often sweet smell.Basil is one of the main ingredients in pesto—a green Italian oil-and-herb sauce. Its other main ingredients are olive oil, garlic, and pine nuts.