| United Kingdom |
a nation in northwestern Europe on the islands of Great Britain and Ireland and made up of England, Scotland, Wales, and Northern Ireland (usually used with "the"). London is the capital of the United Kingdom. |
| United Nations |
(used with a singular or plural verb) an organization of many nations started in 1945 to promote world peace and understanding. |
| United States |
a North American country extending from the Atlantic to the Pacific between Canada and Mexico and including Alaska and Hawaii, also known as "United States of America" (usu. prec. by "the"). |
| United States of America |
a country in North America (usually used with "the"). Washington, D.C., is the capital of the United States of America. |
| unity |
the condition of being united or of acting as one. |
| universal |
of, having to do with, or characteristic of the whole world or the world's population. [2 definitions] |
| universe |
all matter and energy; all existing things, including the earth and heavens. |
| university |
a large school, where people both learn and do research. A student must finish high school before attending a university. Universities offer several levels of degrees. |
| unkind |
not kind or sympathetic; harsh. |
| unknown |
not known; not familiar. |
| unlawful |
not allowed by law; illegal. |
| unless |
except on the condition that. |
| unlike |
not alike or equal; different; unequal. [3 definitions] |
| unlimited |
having no limits, bounds, or restrictions. |
| unload |
to remove the load from. [3 definitions] |
| unlock |
to open the lock of by turning a key or mechanism. [3 definitions] |
| unlucky |
marked by or involving ill fortune or bad luck. [2 definitions] |
| unmanned |
not having a human pilot or crew. |
| unnatural |
not according to natural laws or processes. [2 definitions] |
| unnecessary |
not needed or required. |
| unpack |
to take out of a package, suitcase, or container. [2 definitions] |