U is the twenty-first letter in the basic modern Latin alphabet. Its name in English is spelled u; the plural is ues, though this is rare.Brown & Kiddle (1870) The institutes of English grammar, p 19. Ues is the plural of the name of the letter; the plural of the letter itself is U's, Us, u's, or us. History The letter U ultimately comes from the Semitic letter Waw by way of the letter V. See the letter V for details. During the late Middle Ages, two forms of "v" developed, which were both used… (More on U)