Basil (Ocimum basilicum) (pronounced BAY-zl or BAZZ-il), of the Family Lamiaceae, is also known as Sweet Basil or Tulsi. It is a tender low-growing herb that is grown as a perennial in warm, tropical climates. Basil is originally native to India and other tropical regions of Asia, having been cultivated there for more than 5,000 years. It is prominently featured in varied cuisines throughout the world including Italian, Thai, Vietnamese and Laotian. It grows to between 20–60 cm tall, with opposite, light green, silky leaves 1.5–5 cm long and 1–3 cm broad. The flowers are quite big, white in color and arranged in a terminal spike. Unusual among Lamiaceae, the four stamens and the pistil are not pushed under the upper lip of the corolla, but lay over the inferior. After entomophilous pollination, the corolla falls off and four round achenes develop inside the bilabiate calyx. The plant tastes somewhat like anise, with a strong, pungent, sweet smell. Basil is very sensitive to cold, with best growth in hot, dry conditions. While most common varieties are treated as annuals, some are perennial, including African Blue and Holy Thai basil.
The word basil comes from the Greek βασιλεύς (basileus), meaning "king", as it is believed to have grown above the spot where |St. Constantine and Helen discovered the Holy Cross. The Oxford English Dictionary quotes speculations that basil may have been used in "some royal unguent, bath, or medicine". Basil is still considered the "king of herbs" by many cookery authors. An alternative etymology has "basil" coming from the Latin word basilicus, meaning dragon and being the root for basilisk, but this likely was a linguistic reworking of the word as brought from Greece.