U

U 21st letter of the alphabet , corresponding to the Greek upsilon [Gr.,=u without the aspirate]. Until the late Middle Ages the capital was V, the minuscule u, no distinction being made between the consonantal and vocalic uses of the letter. The fixing of modern orthography, however, has restricted u to the vowel, v to the consonant. In phonetics ŭ usually represents a high back rounded vowel, rather like oo in foot; English ū is a triphthong of y, oo, and w as in utensil; the Continental ū, or oo, is a diphthong of oo and w, as in glue. In chemistry, U is the symbol of the element uranium .

U. The twenty-first letter of the modern English alphabet is represented by ur [blackthorn] in the ogham alphabet of early Ireland.

U¹ / yoō/ (also u) • n. (pl. Us or U's ) 1. the twenty-first letter of the alphabet. ∎  denoting the next after T in a set of items, categories, etc. 2. (U) a shape like that of a capital U, esp. a cross section: [in comb.] U-shaped glaciated valleys. U² • symb. the chemical element uranium. U³ • adj. inf., chiefly Brit. (of language or social behavior) characteristic of or appropriate to the upper social classes: U manners. U⁴ / oō/ • n. a Burmese title of respect before a man's name, equivalent to Mr.: U Thien San.