- any of several aromatic herbs belonging to the genus Ocimum, of the mint family: prized for its savory green leaves, sweet basil (O. basilicum) has more than 150 culinary cultivars, including the tiny-leafed bush basil , the large-leafed mammoth basil , and the purple-leafed dark opal basil .
- bishop of Caesarea in Asia Minor (brother of Saint Gregory of Nyssa).
- a male given name: from a Greek word meaning “royal.”
- a Eurasian plant, Ocimum basilicum, having spikes of small white flowers and aromatic leaves used as herbs for seasoning: family Lamiaceae (labiates)
- a European plant, Satureja vulgaris (or Clinopodium vulgare), with dense clusters of small pink or whitish flowers: family Lamiaceae
- a European plant, Acinos arvensis, having clusters of small violet-and-white flowers: family Lamiaceae
- Saint, called the Great, ?329–379 ad, Greek patriarch: an opponent of Arianism and one of the founders of monasticism. Feast day: Jan 2, June 14, or Jan 1
