What is capitalization of significant words applied to in the United States besides titles?
As regards publication titles it is, however, a common typographic practice among both British and U.S. publishers to capitalise significant words (and in the United States, this is often applied to headings, too). This family of typographic conventions is usually called title case. For example, R. M. Ritter's Oxford Manual of Style (2002) suggests capitalising "the first word and all nouns, pronouns, adjectives, verbs and adverbs, but generally not articles, conjunctions and short prepositions". This is an old form of emphasis, similar to the more modern practice of using a larger or boldface font for titles. The rules for which words to capitalise are not based on any grammatically inherent correct/incorrect distinction and are not universally standardized; they are arbitrary and differ between style guides, although in most styles they tend to follow a few strong conventions, as follows: