Black tea is a type of tea that is more oxidized than oolong, green, and white tea. Black tea is generally stronger in flavor than the less oxidized teas. All four types are made from leaves of the shrub(or small tree) Camellia sinensis. Two principal varieties of the species are used – the small-leaved Chinese variety plant (C. Sinensis subsp. Sinensis), used for most other types of teas, and the large-leaved Assamese plant (C. Sinensis subsp. assamica), which was traditionally mainly used for black tea, although in recent years some green and white have been produced.
In Chinese and the languages of neighboring countries, black tea is known as “red tea”, a description of the color of the liquid; the Western term “black tea” refers to the color of the oxidized leaves. In Chinese, “black tea” is a commonly used classification for post-fermented teas, such as Pu-erh tea; outside of China and its neighboring countries, “red tea” more commonly refers to rooibos, a South African herbal tea. While green tea usually loses its flavor within a year, black tea retains its flavor for several years.