Rice is a type of grain. A little less than half of the population of the earth eats some kind of rice as a staple food. There have come to be a great many varieties of rice, including basmati, jasmine and arborio.
Wild rice is not really a rice but the seed of an aquatic grass that is native to the United States.
Brown rice is rice that has been hulled but has been allowed to keep the bran. It has more nutrients than polished white rice and is especially high in the B vitamins. However, it takes a longer time to cook than white rice.