U Under. A prepositiongoverning the objective case: The boat rocked under them.’ Unique. Don’t use very more or any other modifier with unique which means one of a kind and therefore cannot vary as a modifier might suggest. Up. A preposition governing the objective case: The ladybug crawled up the scout’s leg.” Upon. See on. Upper case. Capitalized letters (in large, special forms) are said to be upper case.” Letters not capitalized are called “lower case.” Capitals start sentences and perform other functions (see capitalization). U.S. This abbreviation for United States is properly used only as an adjective: That is US. territory However, many less formal styles accept the abbreviation in place of the full name of the country Colorado is in the US Some styles prefer USA if the whole name is not given New York is part of the USA.” Usage.Unlike grammatical rules, principles of usage are more exible, depending on the audience, purpose, and occasion of a statement for guidance as much as on the strictures arrived at by academics or others. Many entries in this book suggest how best to use certain words, constructions, or devices. But in almost every instance, alternative patterns, circumstances, or considerations are noted to give some sense of the range of possibilities and choices available to the writer or speaker. Special dictionaries, style books, and guidebooks on usage can be consulted for further insight into this complex stylistic issue. When in doubt, look fora reliable, authoritative source that is accepted by the audience being addressed.