Time Is On Our Side, Part III: Day and Night
What time is it? You probably answered this question with an easy a.m. or p.m., but saying these abbreviations verbally and writing them down are two very different things. This week I’ll try to simplify these abbreviations by giving a few basic rules.
Morning and Afternoon
The abbreviation a.m. stands for ante meridiem, which means “before noon”; p.m. stands for post meridiem, or “after noon.” The meaning is basically “in the morning” or “in the afternoon,” so if You’re using one of these abbreviations, there’s no need for further time expressions like “in the morning.” When in doubt, read the sentence aloud with the full unabbreviated version and see if it makes sense.
Incorrect Example A: The meeting will be at 10:30 a.m. in the morning. This is essentially saying “10:30 in the morning in the morning,” which is obviously incorrect.
Corrected Example A: The meeting will be at 10:30 a.m.
Of course, if You’re not using a.m. and You’re writing the time out in long form, then “in the morning” is fine:
Example B: The meeting will be at ten thirty in the morning.
Punctuation
You’ve probably seen a.m. and p.m. written all kinds of ways: small capitals, uppercase letters, and lowercase letters?with or without periods. The standard rule is to put a.m. and p.m. in lowercase form, with periods. No italics (the italicized instances in this article are for emphasis). Individual organizations and publications might have their own preferences, but the standard rule is followed by both Chicago and AP style. In the absence of specific guidance, follow the standard rule.
Note also that there’s always a space between the time and a.m. or p.m.
Example C: The parade will start at 10:45 a.m.
There is one very commonly seen exception to the standard rule: the television show Canada AM uses uppercase letters and no periods (curiously, its logo uses lowercase letters and no periods).
Example D: Tune in to Canada AM at 6 a.m.
To Use or Not to Use?
Sometimes you don’t need to include a.m. or p.m. at all. If It’s clear whether you mean morning or afternoon, you can leave off the abbreviation and make your writing even more concise.
Example E: We will meet with our accounting department at 2:30. Unless your office keeps a very unusual schedule, It’s safe to assume you mean 2:30 p.m.
But in the following situation, the abbreviation clarifies it:
Example F: The CEO’s flight will arrive at 6:45 a.m. Adding the abbreviation will avoid risking a CEO furious at being left at the airport for 12 hours.
This wraps up this timely (sorry!) series on time of day. If you need a refresher, click through Part I and Part II. Find out your organization’s preferences for numerals vs. long form and for the styling of a.m. and p.m., and work those into your cheat sheet so You’re always consistent in your treatment of time.
Christina M. Frey is a book editor, literary coach, and lover of great writing. For more tips and techniques for your toolbox, follow her on Twitter (@turntopage2) or visit her blog.