It is very confusing -- the Spanish saw the pod in the Americas and thought it was the same as carob so they called it Algorrobo, their word for carob. The name stuck and even though we now know that it is a different family - the plant family Prosopis. The the pod is called algorrobo and the tree algorroba, at least here. In the desert South Western states it is called Mesquite but I think it is more famous for it's wood than fruit although that will probably change! Both Mesquite/Algorrobo and Carob are all legumenous trees and really do look similar.