The Editor's Manual
Grammar, usage, punctuation, and style resource for editors, writers, and learners of the English language.
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 “queen,” “prince,” “duke,” and “duchess” when used in titles or before a name (“Queen Elizabeth II and Prince Philip, Duke of Edinburgh”). References to a specific person may also be capitalized (“the Queen”).
Words like “pope,” “bishop,” “rabbi,” “reverend,” and “father” are capitalized as religious titles before a name but lowercased as common nouns.
Capitalize kinship titles (mom, dad, uncle, grandma, etc.) when using them as names (“Hi, Mom”), but lowercase them as common nouns (“your mom”).
Capitalize military ranks like “general” and “captain” when used as titles before a name or to address a person. Lowercase them as common nouns.
Capitalize names of people, places, companies, departments, and geographical features. Whether a word is capitalized depends upon whether it is being used as a proper noun or simply as a common noun. In titles and headings, capitalize the first and last words and all other words except articles, prepositions, and conjunctions.
Capitalize words like “sir” and “madam” in a salutation (“Dear Sir or Madam”) and when used before a name or as a title (Sir Sean Connery, Madam President). Otherwise, they are generally lowercased (“Yes, ma’am”).
In headings and book or movie titles, capitalize the first word, last word, and all other words except articles, prepositions, coordinating conjunctions, and the word “to.” Various style guides prescribe additional rules.
The plural of an abbreviation is formed by adding an “s” (URLs, DVDs). Avoid inserting an apostrophe to form the plural. Abbreviated SI units do not have a separate plural form (1 cm and 10 cm). Abbreviated social titles such as “Mr.” and “Mrs.” have nonstandard plurals.