Widely used style guides regarding capitalization of titles and headings include the Gregg Reference Manual, the Chicago Manual of Style (Chicago Style), the American Psychological Association (APA Style), and the Modern Language Association (MLA Style).
Gregg Reference Manual
- Capitalize all words except the following:
- Articles such as a, an, and the.
- Short conjunctions such as and, as, but, if, or, and nor.
- Short prepositions such as at, by, for, in, of, off, on, out, to, and up.
- Articles, short conjunctions, and short prepositions should be capitalized as follows:
- Capitalize the first and last words of titles, no matter the length of the words.
- Capitalize the word the at the beginning of a title only if it is actually part of the title.
- Capitalize the first word following a dash or colon in a title.
- Capitalize words such as in, out, off, up, and by in titles when they serve as adverbs rather than as prepositions.
- Capitalize short prepositions such as up, in, on, and for when used together with prepositions having four or more letters.
Chicago Manual of Style
Principles of Headline-Style Capitalization
- The conventions of headline style are governed mainly by emphasis and grammar. The following rules, though occasionally arbitrary, are intended primarily to facilitate the consistent styling of titles mentioned or cited in text and notes.
- Capitalize the first and last words in titles and subtitles (but see rule 7), and capitalize all other major words (nouns, pronouns, verbs, adjectives, adverbs, and some conjunctions—but see rule 4).
- Lowercase the articles the, a, and an.
- Lowercase prepositions, regardless of length, except when they are used adverbially or adjectivally (up in Look Up, down in Turn Down, on in The On Button, to in Come To, etc.) or when they compose part of a Latin expression used adjectivally or adverbially (De Facto, In Vitro, etc.).
- Lowercase the conjunctions and, but, for, or, and nor.
- Lowercase to not only as a preposition (rule 3) but also as part of an infinitive (to Run, to Hide, etc.), and lowercase as in any grammatical function.
- Lowercase the part of a proper name that would be lowercased in text, such as de or von.
- Lowercase the second part of a species name, such as fulvescens in Acipenser fulvescens, even if it is the last word in a title or subtitle.
American Psychological Association (APA) Style
Words Beginning a Sentence
- Capitalize the first word in a complete sentence.
- Capitalize the first word after a colon that begins a complete sentence.
Major Words in Titles and Headings
- Capitalize major words in titles of books and articles within the body of the paper.
- Capitalize conjunctions, articles, and short prepositions are not considered major words; however, capitalize all words of four letters or more.
- Capitalize all verbs (including linking verbs), nouns, adjectives, adverbs, and pronouns.
- When a capitalized word is a hyphenated compound, capitalize both words. Also, capitalize the first word after a colon or a dash in a title.
- Exception: In titles of books and articles in reference lists, capitalize only the first word, the first word after a colon or em dash, and proper nouns. Do not capitalize the second word of a hyphenated compound.
Proper Nouns and Trade Names
- Capitalize proper nouns and adjectives and words used as proper nouns. Proper adjectives that have acquired a common meaning are not capitalized; consult Merriam-Webster's Collegiate Dictionary (2005) for guidance.
- Capitalize names of university departments if they refer to a specific department within a specific university and complete names of academic courses if they refer to a specific course.
- Capitalize trade and brand names of drugs, equipment, and food.
- Do not capitalize names of laws, theories, models, statistical procedures, or hypotheses.
Nouns Followed by Numerals or Letters
- Capitalize nouns followed by numerals or letters that denote a specific place in a numbered series.
- Exception: Do not capitalize nouns that denote common parts of books or tables fol lowed by numerals or letters.
- Do not capitalize nouns that precede a variable.
Titles of Tests
- Capitalize exact, complete titles of published and unpublished tests. Words such as test or scale are not capitalized if they refer to subscales of tests.
- Do not capitalize shortened, inexact, or generic titles of tests.
Names of Conditions or Groups in an Experiment
- Do not capitalize names of conditions or groups in an experiment.
Names of Factors, Variables, and Effects
- Capitalize names of derived variables within a factor or principal components analy sis. The words factor and component are not capitalized unless followed by a number.
- Do not capitalize effects or variables unless they appear with multiplication signs.
Modern Language Association (MLA) Style
Titles of Works in the Research Paper
- In a title or a subtitle, capitalize the first word, the last word, and all principal words, including those that follow hyphens in compound terms. Therefore, capitalize the following parts of speech:
- Do not capitalize the following parts of speech when they fall in the middle of a title:
- Coordinating conjunctions
- The to in infinitives
- Use a colon and a space to separate a title from a subtitle, unless the title ends in a question mark or an exclamation point. Include other punctuation only if it is part of the title or subtitle.
Gregg Reference Manual
- In a heading or title, capitalize all the elements except articles (a, an, and the), short prepositions (at, by, for, in, of, off, on, out, to, and up), and short conjunctions (and, as, but, if, or, and nor).
Chicago Manual of Style
- Hyphenated compounds in headline-style titles:
- Simple Rule
- Capitalize only the first element of a hyphenated word unless any subsequent element is a proper noun or adjective.
- Traditional Rules
- Always capitalize the first element.
- Capitalize any subsequent elements unless they are articles, prepositions, coordinating conjunctions (and, but, for, or, nor) or such modifiers as flat or sharp following musical key symbols.
- If the first element is merely a prefix or combining form that could not stand by itself as a word (anti, pre, etc.), do not capitalize the second element unless it is a proper noun or proper adjective.
- Do not capitalize the second element in a hyphenated spelled-out number.
- Break a rule when it doesn't work, e.g., Run-ins and Take-offs (lowercase short and unstressed elements).
Retinal Hemangioblastoma in von Hippel–Lindau Disease
Von Recklinghausen's Disease and Breast Cancer
Autism in Children Born After In Vitro Fertilization
A Fine-Scale Chimpanzee Genetic Map from Population Sequencing
Stepwise Screening of Atrial Fibrillation in a 75-Year-Old Population: Implications for Stroke Prevention
- Sabin, William A. (2011). The Gregg reference manual : a manual of style, grammar, usage, and formattin. New York: McGraw-Hill. ISBN 0-07-339710-5.
- The Chicago manual of sty. Chicago: The University of Chicago Press. 2010. ISBN 0-226-10420-6.
- Publication manual of the American Psychological Associati. Washington, DC: American Psychological Association. 2010. ISBN 1-4338-0561-8.
- Gibaldi, Joseph (2009). MLA handbook for writers of research pape. New York: Modern Language Association of America. ISBN 978-1-60329-024-1.