AM and PM – Definition

What does AM and PM stand for?

Most people know that A.M. stands for “ante meridiem” or “before midday” and P.M. stands for “post meridiem” or “after midday”. However, many don’t know the origins of these terms or how they came to be used to designate morning and afternoon/evening.

The Latin phrases “ante meridiem” and “post meridiem” are the two halves of the Latin phrase “horā post meridiēm” which translates to “after midday”. The phrase was abbreviated as “P.M.” in Roman times and eventually made its way into English.

As for “A.M.”, this is simply an abbreviation of the Latin phrase “annō Domini nostrī Jesu Christi” which means “in the year of our Lord Jesus Christ”. This was commonly used to denote dates in medieval manuscripts and eventually became shorthand for denoting morning hours.. For more information visit AM en PM

AM stands for Ante Meridiem, which means “before midday” in Latin. PM stands for Post Meridiem, which means “after midday” in Latin.

Ante Meridiem

The term “ante meridiem” is derived from the Latin words for “before midday.” This time period is typically abbreviated as “a.m.” or “am,” and it refers to the hours of the day before noon.

In most cases, ante meridiem hours are counted from midnight to noon. For example, if someone says they will meet you at 10 a.m., they are referring to a meeting time that is 10 hours after midnight. Similarly, if an event is scheduled for 11:59 p.m., it will take place in the ante meridiem hours of the following day – in other words, it will occur during the last minute of the day before noon.

While ante meridiem technically refers to the time before noon, many people use it interchangeably with “morning.” In fact, some dictionaries list “ante meridiem” as a synonym for “morning.”

So, if you find yourself wondering whether something is happening in the morning or in the ante meridiem hours, chances are it’s happening during both!

The term “ante meridiem” (a.m.) is used to describe the morning hours before noon. The phrase originates from the Latin words for “before midday.” In the 24-hour clock system, ante meridiem hours are numbered from midnight to noon (1:00 a.m. to 12:00 p.m.).

The abbreviations a.m. and p.m. are commonly used in English, although they are not always necessary. For example, you can say “I wake up at 7 every morning” instead of “I wake up at 7 a.m..”

When written in full, ante meridiem should be lowercase and followed by a period (full stop). The plural form, ante meridia, is very rare and is not used in contemporary English.

Post Meridiem

The term “post meridiem” (abbreviated “p.m.”) is used to refer to the time after noon. This time period includes the hours from 12:01 p.m. to 11:59 p.m., and is often considered to be the afternoon and evening.

In Latin, the term “post meridiem” literally means “after midday.” This can be a confusing term for English speakers, since the word “midday” in English can refer to either noon or 12:00 p.m. In Latin, however, the word “meridiem” always refers to noon. As a result, “post meridiem” simply means “after noon.”

While the terms “a.m.” and “p.m.” are used in English, other languages use different terms to divide up the day. For example, in French, the term “après-midi” is used for the time period from 2:00 p.m. to 6:00 p.m., while the term “soirée” is used for the time period from 6:00 p.m. to 10:00 p.m..

It’s important to note that many events are scheduled using a 24-hour clock, which does not use the terms “a.m.” or “p

Post meridiem (Latin for “after midday”) is a designation used to indicate that an event or task occurred after noon. The 24-hour clock, commonly used in the United States and other countries, counts the hours from midnight to noon as “12 AM” and the hours from noon to midnight as “12 PM.” Hence, 12:01 PM would be one minute past noon, and 12:00 AM would be midnight. Because of this system, post meridiem is often abbreviated as “p.m.”

When did AM and PM come about?

The modern day 24 hour clock can be traced back to the Egyptians, who divided their day into 10 daytime hours and 14 nighttime hours. The first recorded use of the term “ante meridiem” (AM) and “post meridiem” (PM) is from a.d. 1267, in the work Computus by Roger Bacon. In this work, Bacon discusses how to calculate the time of Easter using a table that includes AM and PM.

It wasn’t until 1687, however, that the use of AM and PM became widespread with the publication of Geminiano Montanari’s book on astronomy, Opera dell’arte del misurare. In this book, Montanari uses AM and PM to designate the two halves of the day, with AM corresponding to the period from midnight to noon, and PM corresponding to the period from noon to midnight.

The use of AM and PM became even more commonplace with the invention of mechanical clocks in the 18th century. These clocks typically had two dials – one for AM and one for PM – which made it easy to indicate which half of the day was being represented. Today, most digital clocks also include AM and PM indicators.

The terms “am” and “pm” come from the Latin phrases “ante meridiem” and “post meridiem.” These translate to “before midday” and “after midday,” respectively. The abbreviations “a.m.” and “p.m.” first became widely used in the 17th century.

The use of “am” and “pm” to designate the time of day dates back to ancient Rome, though at that time they were written as A.M. (ante meridiem, or before midday) and P.M. (post meridiem, or after midday). However, it wasn’t until the 1700s that the abbreviations a.m. and p.m., as we know them today, became widely used.

While there is no one definitive answer as to how or why these particular abbreviations came to be used, there are several theories on the subject:

Some believe that am/pm arose out of a need for greater precision when referring to half-day periods (as opposed to using just A/P).

Another theory suggests that am/pm were originally intended to indicate whether an event was taking place before or after noon (hence ante meridiem and post meridiem).

Still others believe that am/pm were simply shortened versions of

How do we use AM and PM

AM and PM are abbreviations for ante meridiem and post meridiem. These terms are used to designate different time periods in the day. AM is used for the period from midnight until noon, while PM is used for the period from noon until midnight.

The use of AM and PM can be seen in many places, including on clocks, in timetables, and in written correspondence. When writing the time, it is common to use a 12-hour clock, with AM and PM indicators. For example, 8:00 AM would be written as 08:00 AM, while 8:00 PM would be written as 20:00 PM. On a 24-hour clock, AM and PM are not used, and the time is instead divided into 24 hours, with midnight being 00:00 and midday being 12:00.