The Editor's Manual
Free learning resource on English grammar, punctuation, usage, and style.
Round brackets are called “parentheses” in American English but referred to simply as “brackets” in British English. In American writing, square brackets are used within parentheses, while the British use round within round brackets (nested parentheses).
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.
Form the plural of a given or a family name by adding “s.” If the name ends in a sibilant sound (like “s,” “x,” “z”), add “es” instead.
Add “s” to form the plural of a name ending in a vowel. Don’t add “es,” even for names ending in “i” or “o.” Simply add “s” (“the Rossis,” not “Rossies”). Avoid using an apostrophe (“the Lees,” not “Lee’s”).
Form the plural of a name ending in “z,” “x,” “sh,” “s,” and other sibilant sounds by adding “-es” without an apostrophe (“the Diazes,” “the Hendrixes,” “the Williamses”).
Form the plural of a name ending in “s” by adding “es,” not “ses” or an apostrophe and “s” (“the Harrises,” not “Harrisses” or “Harris’s”).