The Editor’s Manual
Free learning resource on English grammar, punctuation, usage, and style.
Capitalize names of holidays, such as “Christmas” and “Hanukkah.” Don’t capitalize adjectives like “happy” and “merry” or common nouns like the word “holidays,” unless at the start of a sentence.
Don’t capitalize phrases like “happy birthday” when talking about wishing someone. Feel free to capitalize them in personal greetings.
The greeting is “Happy New Year,” not “Happy New Years” or “Happy New Year’s.” It contains a singular noun (“year”) and requires no apostrophe.
Don’t capitalize greetings like “good morning” except at the start of a sentence. Capitalize all words in an email salutation if it stands alone but only the first word if followed by a name.
Initialisms and acronyms generally contain all capital letters, although Latin, technical, and scientific abbreviations are often lowercased. Contracted social titles and proper nouns are capitalized.
Don’t capitalize a word after a colon within a sentence, or a single sentence after a colon. Capitalize a question or a series of two or more sentences introduced by a colon. Also capitalize subtitles.
Capitalize specific time periods (Middle Ages), but lowercase descriptive terms (medieval times). Also capitalize proper names (Victorian era) and geological time periods (the Jurassic).
Avoid capitalizing corporate job titles when used descriptively or as common nouns. Capitalize them when used as part of a name or to address a person.
Capitalize words like “professor” and “principal” as titles before a name, but not when used descriptively after a name or as common nouns.
Capitalize words like “king,” “prince,” “duke,” and “duchess” when used in titles or before a name (“King Charles III, son of Queen Elizabeth II and Prince Philip, Duke of Edinburgh”). References to a specific person may also be capitalized (“the King”).