Ceratonia siliqua, commonly known as the carob tree, St John's-bread, or locust bean (not to be confused with the African locust bean) is a species of flowering evergreen shrub or tree in the pea family, Fabaceae. It is widely cultivated for its edible pods, and as an ornamental tree in gardens. The ripe, dried pod is often ground to carob powder which is used as a substitute for cocoa powder.
It is native to the Mediterranean region including Southern Europe, Northern Africa, the larger Mediterranean islands; to the Levant and Middle-East of Western Asia into Iran; and to the Canary Islands and Macaronesia. The word Carat, a unit of purity for gold alloys, was derived from the Greek word kerátion literally meaning a small horn, and referring to the carob seed as a unit of weight.