The Ambiguity of “12:00 A.M.” and “12:00 P.M.”
by Ken Bresler
The Vocabula Review, October 2014
There’s no such thing as “12:00 A.M.” or “12 P.M.” Stay with me as I walk us through this.
The prefix “ante” means “before.” (We’re not talking “anti,” which means “against.”) “Ante,” as in “antebellum mansion” or “antebellum plantation.” “Antebellum” as in “before the war,” more specifically, the Civil War. So an antebellum mansion predates the Civil War. It antedates it, if you will. And this antebellum mansion might have an anteroom.
Now onto “diem,” which is Latin for “day.” You might get paid by the day – per diem. If you get a daily meal allowance, you’re getting a per diem. “Carpe diem” (pronounced “car-pay dee-em”) is the admonition to “Seize the day.”
“Meri” means “mid. Thus, “meridiem” means “midday” – in other words, noon. Meridiem = noon.
“P.M.” stands for “post-meridiem” – the time after noon. “Post,” of course, means “after,” as in “postseason play.”
Now back to “ante.” “A.M.” stands for “ante-meridiem” – before noon. “A.M” means before noon. “P.M.” means after noon. Is noon A.M. or P.M.? Neither. Noon is noon. Noon cannot be “before noon” and it cannot be “after noon.” Noon is the dividing line between A.M. and P.M. Noon is neither A.M. nor P.M.
Asking whether noon is A.M. or P.M. is like asking whether the border between the United States and Canada is in the U.S. or Canada. It’s in neither country; that’s the point of the border.
Is the border between the Eastern Standard Time zone and the Central Standard Time zone in the EST zone or the CST zone? Neither.
Nonetheless, people do write “12:00 A.M.” and “12:00 P.M.” And some on-line forms asking for scheduling information ask you to designate 12:00 as either A.M. or P.M. Aside from the fact that there is no such time as “12:00 A.M.,” is that term supposed to mean 12:00 noon or 12:00 midnight? Aside from the fact that there is no such time as “12:00 P.M.,” is that term supposed to mean 12:00 noon or 12:00 midnight? More important than that the terms “12:00 A.M.” and “12:00 P.M.” are wrong is that they’re ambiguous.
Sometimes the context makes “12:00 A.M.” and “12:00 P.M.” clearer. Consider this ordinance that was at issue before a federal appeals court: “Moon Ordinance No. 96 permits canvassing 9:00 A.M. to 4:00 P.M. Monday through Friday and 9:00 A.M. to 12:00 P.M. on Saturday.”
So we ponder this a while, as did Edgar Allan Poe, who wrote, “Once upon a midnight dreary, while I pondered weak and weary.”
If a canvasser may solicit people at their homes from 9:00 A.M. to 4:00 P.M. on Monday through Friday, may the canvasser do so on Saturday until 12:00 midnight or 12:00 noon? We have to assume that canvassing ends at noon. But it’s only an assumption and we had to ponder it a while. (By the way, that ordinance was discussed in Pennsylvania Alliance for Jobs and Energy v. Council of the Borough of Munhall, 743 F.2d 182, 195 n.2 (3rd Cir. 1984).)
However, context does not always make the ambiguity clearer.
The solution to the ambiguity?Just write “12:00 noon” and “12:00 midnight.”
Problem solved? Almost, but an ambiguity remains: the ambiguity of “12:00 midnight.”
Does “12:00 midnight” belong to the day that comes before midnight or the day that comes after midnight? Neither. It’s the dividing line. So if a contract requires a party to do something “by 12:00 midnight on July 15,” does the contract refer to the midnight dividing July 14 and 15, or the midnight dividing July 15 and 16? Does the party have all of July 14 to comply, and when July 14 is over, compliance must begin? Or does the party have all of July 15, and one second into July 16 is past the deadline?
To resolve this ambiguity, consider using language such as this: “before July 15 at 11:59 P.M.” or “before July 15 at 12:00:01 A.M.” or “by the midnight before July 16.”
And if your loved one is leaving on the “Midnight Train to Georgia,” as the song sung by Gladys Knight goes, make sure you know which midnight he or she means. Otherwise, you might miss meeting the train, or be waiting at the station on the wrong day.
***
Addendum to The Vocabula Review article: When I presented this lesson at Northeastern University Law School, one of my students pointed out that “12:00 noon” and “12:00 midnight” can be shortened to “noon” and “midnight.”
And I learned how the ambiguity of 12:00 a.m. and 12:00 p.m. held up a pizza order. In October 2014, a legal research company ordered pizza on-line for delivery at 12:00 p.m.to a training session at the law school. When noon arrived and the pizzas didn’t, the trainers called the pizza store to find out where the order was. To the trainers, 12:00 p.m. meant noon; to the pizza store, 12:00 p.m. meant midnight. The store was planning for a midnight delivery almost 12 hours later.
The context did not resolve the ambiguity. To a pizza store, a midnight order of pizza can be reasonable. People do order and eat pizza at that hour. And a law school is populated by young people who keep variable hours. The store accepted responsibility for the miscommunication and delivered pizzas around 12:30 p.m. at a discount. It saved good will and lost money.
Not only can ambiguities in designating time leave a contract fuzzy, they can leave you hungry.