The Editor's Manual
Grammar, usage, punctuation, and style resource for editors, writers, and learners of the English language.
“That” introduces information that is essential to meaning and not enclosed in commas. “Which” introduces additional, optional details enclosed in commas. In British usage, it also introduces essential information.
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.
Use a colon to introduce a list or a quotation, or to explain and amplify a statement. It directs the reader’s attention to the information that follows. It can also serve as a sign or separator.
Use an apostrophe with possessives (New Year’s Day, Mother’s Day, Presidents’ Day) but not with descriptive terms (Veterans Day, Human Rights Day).
Use commas before and after the year in the American date format (May 1, 2021) but not in British (1 May 2021). No comma is needed when only the month and year are specified (May 2021).
American date format is month-day-year (May 1, 2021); British is day-month-year (1 May 2021). Use commas between day and year in American English; no commas are needed in dates in British English.
To show the exact date, spell out the month, and write the day and year in numerals (May 1, 2021, or 1 May 2021). Don’t place a comma between month and year (May 2021). Spell out the day when it stands alone.
Write years in numerals. Say the year in two parts: the first two and then the second two digits. In words, write the year as it would be pronounced.
BCE and CE are religiously neutral alternatives to BC and AD. While BC, BCE, and CE appear after the date (223 BC), AD appears before (AD 1776). Periods are optional and generally omitted.
Capitalize specific time periods (Middle Ages), but lowercase descriptive terms (medieval times). Also capitalize proper names (Victorian era) and geological time periods (the Jurassic).