Leah Berenson
Leah Berenson
March 6, 2024 ·  3 min read

Some People Are Only Just Figuring Out What AM and PM Stand For

Most people know that AM and PM represent morning and afternoon, or night. However, few people actually know what the abbreviations mean, or how to use them properly.

Questioning AM and PM

Amaya Clarke posted a video on TikTok, posing the question, “What does AM and PM stand for?” Unsurprisingly, most people had a general understanding that AM and PM refer to morning or afternoon and night. However, many people incorrectly answered due to not knowing what the abbreviations stand for, or how to use them properly. “Well, I didn’t know this and I’m in my 50’s! Was never taught this in school either.” Exclaimed one user. “I’m in my 30s and never heard of this and no they never taught this in any school I went to lol,” disclosed another person.

Clarifying AM and PM

First, AM and PM are most commonly lower-case letters. Next, they’re properly punctuated with periods between the letters. For example, a.m. and p.m. So, what do they mean? AM refers to the morning, and stands for “ante meridiem,” meaning “before midday”. “This is the time before the sun has crossed the meridian.” According to RMG. Meanwhile, PM refers to “after midday” and stands for “post meridiem.

Therefore, a.m. refers to the hours between 12 a.m. or midnight through 12 p.m. or noon. Conversely, the hours between noon and midnight are p.m.

Use of Military Time

The U.S. is one of many countries that uses a 12-hour clock format. However, the U.S. Military operates on a 24-hour clock. Similarly, other countries like France and Germany also use a 24-hour clock. Although nations have been using 24-hour clocks for centuries, this method for telling time became adopted by the U.S. Military around 1920. Seemingly, a more practical way of “coordinating military operations,” according to US Army Basic.

The military doesn’t use AM and PM. Instead, the hours are 00:00, or midnight, through 23:59 or 11:59 p.m. For example, 1 a.m. would be 1:00, whereas 1 p.m. would be 13:00. Meanwhile, 17:00 would be 5 p.m. An easy way to remember this is to subtract 12 from whatever time it is in the afternoon.

Interestingly, because noon and midnight don’t technically fall into either AM or PM, they would simply be referred to as noon and midnight.

Tracking Time is Essential

Time is a strange concept, far more complicated than simply understanding a 12-hour or 24-hour clock. For centuries, scientists have tracked the movement of planets and stars to better understand the age of our universe or how much time it has been around. Time has also played a vital role in how people function, dating back to our earliest ancestors. Hunters would need to track the time of day they would most likely catch a meal and the changing seasons. On the other hand, most people would prefer not to live by time constraints. Few feel that there is enough time in a day to accomplish everything, and even fewer want to get up and face a work week with set hours.

Therefore, time is as necessary as it is a grievance. Although there is little we can do to eliminate the time constraints we face, understanding AM and PM will, at the very least, help us better keep track of our obligations.

Read More: People Disturbed After Finding Out Why Pupils Go Red in Photos


  1. History of Military Time.” US Army Basic. August 30, 2023.
  2. Is noon 12am or 12pm?RMG
  3. Which Countries Use 24 Hour Time in 2024?WPR
  4. People are only just finding out what AM and PM stand for.JOE. Callum Boyle. February 27, 2024.
  5. OK, What Do ‘A.M.’ and ‘P.M.’ Actually Stand For?Parade. LAKEISHA FLEMING. August 14, 2023
  6. A brief history of time: What is it and how do we define it?Astronomy. Raymond Shubinski. January 6, 2022.