carob, leguminous evergreen tree (Ceratonia siliqua) of the family Leguminosae (pulse family), native to Mediterranean regions but cultivated in other warm climates, including Florida and California. The large red pods have been used for food for animal and man since prehistoric times. The pods and their extracted content have numerous common names, e.g., locust bean gum and St.-John's-bread—the latter from the belief that they may have been the "locust" eaten by John the Baptist in the wilderness (Mark 1.6). Carob is used also for curing tobacco, in papermaking, and as a stabilizer in food products. It has been claimed that the seeds were the original of the carat, the measure of weight for precious jewels and metals. Carob is classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Leguminosae.