U is for Unique.
u·nique [yoo-neek]adjective1. existing as the only one or as the sole example; single; solitary in type or characteristics: a unique copy of an ancient manuscript.2. having no like or equal; unparalleled; incomparable: Bach was unique in his handling of counterpoint.3. limited in occurrence to a given class, situation, or area: a species unique to Australia.4. limited to a single outcome or result; without alternative possibilities: Certain types of problems have unique solutions.5. not typical; unusual: She has a very unique smile.