Although you might think that you ate yam with your turkey last Thanksgiving, the odds are that you did not; instead, you probably had sweet potato, a tuber that is often incorrectly referred to as yam. In fact, despite resembling each other in size, shape, and taste, the sweet potato and the yam are not related as plants and are distinct in origin: the sweet potato, which has long been cultivated and sold in North America, is indigenous to South America, while the yam, which is rarely sold in North America, is indigenous to Africa. The confusion of sweet potatoes and yams dates back to the mid-seventeenth century when slaves taken from West Africa to the United States transferred a name familiar to them—yam—to the American sweet potato. The word yam had, however, been in use in English before this time as a name for the true, African tuber. This “proper” use of yam dates back to the end of the sixteenth century, when English borrowed the Spanish name for the African tuber—igname—and changed the spelling and pronunciation to yam. The Spanish, in turn, had derived their word igname from one of several West African names for the tuber: perhaps the Hausa nama, which not only denoted the yam but also meant flesh, or the Swahili nyama, also meaning meat, or the Fulah nyama, also meaning to eat—all these West African words ultimately derive from the same source. The fact that yam derives from West African words meaning flesh, meat, and to eat suggests what an important food yams must have been in these cultures. Incidentally, the scientific name of the yam is Dioscorea Batatas, noteworthy because it is the only major vegetable to take its scientific name from a real person: Pedanius Dioscorides, a Greek physician who is considered to have founded the science of botany nearly two thousand years ago.
Yams, which are subterranean and characterized by their yellow or orange hue, belong to a tropical vine that bears resemblance to sweet potatoes but are known to be richer in both sweetness and succulence, as well as being more deeply pigmented. They are typically prepared through the process of boiling or baking and are often flavored with either savory notes of salt and pepper or sweetened with the addition of brown sugar.
The luscious edible tuber of a tropical vine bears a resemblance to the beloved sweet potato. From this tuber, a starchy substance akin to arrowroot is extracted, showcasing its versatility as a valuable culinary ingredient.