The term 'SWEET POTATO RELATIVE' can be summarized by the crossword solution 'YAM, ' which is a three-letter word. Yams are a type of root vegetable that are closely related to sweet potatoes. They are native to Africa, Asia, and the Caribbean, and are an important part of many traditional diets. Yams have a rough, scaly skin and are usually white, yellow, or purple in color. They are often used in stews, soups, and other dishes.