(亦作u)
(pl. Us 或U's)
1
- the twenty-first letter of the alphabet英语字母表中第二十一个字母。
1.1
- denoting the next after T in a set of items, categories, etc.U项, U类（一组项目、分类中的第二十一位）。
2
U
a shape like that of a capital U, especially a cross section（尤指横截面）U字形：in combination U-shaped glaciated valleys.U字形冰蚀谷。
1.1
- (in names of sports clubs) United.（体育俱乐部名）同United:
Newcastle U.
纽卡斯尔联队。
1.2
- Brit. universal (denoting films classified as suitable without restriction).〈英〉（电影分级）同UNIVERSAL.
1.3
- Uruguay (international vehicle registration).同URUGUAY（国际车辆注册用语）。
- the chemical element uranium铀, 铀元素。
- informal, chiefly Brit. (of language or social behaviour) characteristic of or appropriate to the upper social classes〈非正式, 主英〉（语言, 社会行为）上流社会的, 上等阶层的：
U manners.
上流社会的礼仪。
词源
abbreviation of UPPER CLASS; coined in 1954 by Alan S. C. Ross, professor of linguistics, the term was popularized by its use in Nancy Mitford's Noblesse Oblige (1956).