The Editor’s Manual
Free learning resource on English grammar, punctuation, usage, and style.
Parentheses set off information that may be useful but is tangential to the primary meaning of the passage. Square brackets enclose editorial clarifications to quoted text. Square brackets are also used as brackets within brackets.
Use square brackets within parentheses to show brackets within brackets. In British style, round brackets are used within round brackets. Avoid using nested parentheses in U.S. writing.
Use “sic” to indicate a grammatical or spelling mistake in the original text of a quote. “Sic” is generally italicized in formal texts. Also enclose “sic” in brackets in formal writing.
Brackets enclose editorial comments and corrections, and any text added to a quote by someone other than the original writer. “Sic” in brackets indicates an exact reproduction. Brackets also set off parenthetical material that appears in text already within parentheses.
Use parentheses (or round brackets) to set off supplementary information from surrounding text. Such information should not be essential to the grammar of the sentence. Periods go within parentheses if they belong to the parenthetical matter but outside otherwise.
Use masculine and feminine pronouns like “he” and “she” instead of “it” for animals with names or whose sex is known. To refer to a species or an animal whose sex is not known, use “it” instead.
Use “who” for animals with names, animals that are personified or anthropomorphized, or to indicate emotional closeness. Use “which” or “that” to discuss a species or an unknown animal without a name.
Use “who” as a relative pronoun to link a description to the person it describes. “Who” is used not just for people but also animals with names. “Who” can replace “whom” in informal usage.
Don’t use a comma before “who” when it presents information necessary to meaning (a restrictive clause). Do use a comma when “who” introduces an optional description (a nonrestrictive clause).
Use “each of” with singular verbs to refer to every one of a group separately. “Each of” may be followed by a plural, gender-neutral pronoun. In spoken English, “each of” is sometimes used with plural verbs to refer to an entire group.