titlecase

Title case is a capitalization style used for titles and headings in English. It involves capitalizing the principal words while leaving certain small words in lowercase. It is commonly applied to books, articles, songs, and software names, and is supported by many editors and typesetting systems.

The basic rule is that the first and last words of a title are always capitalized. In addition, most editors capitalize nouns, pronouns, verbs, adjectives, and adverbs. Articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, so, yet), and short prepositions are usually left in lowercase. Some guides differ on the treatment of prepositions, and longer prepositions may be capitalized in others. Style guides may also differ on hyphenated compounds, treating them as a single word or as separate components for capitalization.

Common style guides include the Chicago Manual of Style, the AP Stylebook, and MLA style. Chicago and MLA generally apply capitalization to major words, while AP tends toward more lowercase in headlines and titles, though the first and last words are always capitalized. In practice, many publishers simply enforce a chosen house style, and software tools can convert text to title case according to a selected rule set.

Word processing programs and programming libraries often implement title-case functions, with options to exclude or include certain word classes or to handle hyphenated terms and proper nouns. The choice of rule set can affect cross-language titles, brand names, and stylized terms.