In general, capitalize only when called for by a specific rule in this guide or in one of the guides referenced in the introduction.
Lowercase, also referred to as “down style,” is preferred in modern usage. Avoid the inclination to capitalize to indicate that Something Is Very Important. Also see the University and College References section.
All references to capitalization in this guide are to initial capitals (the first letter of a word), not full capitals (all letters in a word).
Capitalize the following:
- Letter grades
- Proper names (people, organizations, products, etc.)
- Scientific names of plants and animals: Capitalize genus, but not species and subspecies (Homo erectus, Homo sapiens)
- Titles and subtitles; see Names: Titles of Works for additional guidelines
Headline capitalization—also used for course titles:
- Capitalize the first and last words in titles and subtitles, and capitalize all other major words (nouns, pronouns, verbs, adjectives, adverbs, and conjunctions with four or more letters).
- Capitalize words in a hyphenated compound, except after prefixes with fewer than five letters: Cross-Cultural, Co-star.
- 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 (A Priori, De Facto, In Vitro, etc.). A list of common prepositions is available at www.towson.edu/ows/prepositions.htm.
- Lowercase the conjunctions and, but, for, or, and nor.
- 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, even if it is the last word in a title or subtitle: From Homo erectus to Homo sapiens: A Brief History.