AM and PM – Meaning, Full Form of AM PM

Welcome to another exciting exploration of mathematics at Brighterly, where we always aim to make learning a fun and engaging experience for children. Today, we invite you to join us on an intriguing journey through time. In this article, we will explore the meaning and full form of the terms AM and PM. These seemingly simple abbreviations are a significant part of our daily lives, shaping our routines and schedules. We’ll delve into their definitions, origins, and how they differ. We’ll also touch on how to read, write, and convert time in AM and PM. Moreover, we’ll provide insights into international variations in their usage. Let’s set off on this enlightening journey through the sands of time, learning and growing at every moment!

What Are AM and PM?

AM and PM are time conventions used primarily in the 12-hour clock system to distinguish between day and night. AM stands for “Ante Meridiem,” a Latin phrase meaning “before midday.” PM stands for “Post Meridiem,” translating to “after midday.” These abbreviations help to divide the 24 hours of a day into two periods, spanning from midnight to noon (AM), and from noon to midnight (PM).

Definition of AM

AM (Ante Meridiem) is the period of time that starts at midnight (12:00 AM) and ends just before noon (11:59 AM). The term derives from Latin, with “Ante” signifying “before” and “Meridiem” translating to “midday.” Therefore, AM indicates the time segment before the day reaches its mid-point.

Definition of PM

PM (Post Meridiem), on the other hand, starts at noon (12:00 PM) and concludes just before midnight (11:59 PM). This Latin term combines “Post” meaning “after” and “Meridiem” implying “midday.” As such, PM refers to the time period after the day has reached its halfway mark.

Origins of AM and PM

These abbreviations, AM and PM, trace their roots back to the ancient Romans. The Romans divided the day into 24 hours, but unlike our modern system, their day began at sunrise and ended at sunset. The use of AM (Ante Meridiem) and PM (Post Meridiem) became popular during the Middle Ages, as sundials (early time-telling devices) were prevalent.

Understanding AM and PM

AM and PM help us understand the division of a day. Think of a day as a pizza sliced into two equal halves. The first half, from midnight to just before noon, is the AM period. As the day progresses, it switches to the PM period, which lasts from noon until just before midnight. Just remember, mornings are AM, and afternoons through night are PM!

Uses of AM

AM is employed in various facets of daily life. It’s used to schedule morning activities like breakfast, school, or work. It’s also used in transport schedules, television and radio broadcasting, and many other fields. In a nutshell, AM assists in coordinating all morning activities that occur from midnight until noon.

Uses of PM

Similarly, PM plays a crucial role in organizing afternoon to nighttime activities, such as lunch, evening entertainment, or bedtime. It’s also extensively used in public transport schedules, TV and radio programming, among other areas. PM, thus, helps schedule and coordinate all activities taking place from noon until midnight.

Difference Between AM and PM

The primary difference between AM and PM lies in the time of day they represent. While AM denotes the hours from midnight to just before noon, PM indicates the hours from noon to just before midnight. Recognizing the switch between AM and PM is essential for accurate timekeeping.

Reading and Writing Time in AM and PM

When reading and writing time in AM and PM, we use the 12-hour clock system. This means after 12:59 AM, the time resets to 1:00 AM, continuing up to 11:59 AM. At noon, the time changes to 12:00 PM, and the cycle repeats for the PM hours. Always remember to include the AM or PM to specify the time of day.

Converting Time from AM to PM and Vice Versa

When converting time, remember that a day is 24 hours. If it’s 8 AM and you want to find out what time it will be in 6 hours, you’ll add 6 to 8, giving you 2 PM. If it’s 7 PM and you need to know what time it will be in 8 hours, add 8 to 7, but since that goes past midnight, you subtract 12 from the result (15-12), giving you 3 AM.

International Differences in Using AM and PM

While the 12-hour clock system with AM and PM is standard in many parts of the world, including the United States, Canada, Australia, and the Philippines, many other countries use the 24-hour clock, or military time, especially in written communication. For example, in France or Germany, you might see 14:00 instead of 2:00 PM.

Practice Problems on AM and PM

Let’s apply this newfound knowledge with some practice problems! Try converting the following 24-hour clock times to 12-hour clock times:

  1. 13:00
  2. 00:00
  3. 23:00

Answers: 1. 1:00 PM, 2. 12:00 AM, 3. 11:00 PM.


As we wind down our journey through the fascinating world of AM and PM, we hope that you, our Brighterly learners, are walking away with a solid understanding of these fundamental timekeeping concepts. Mastering the meanings, full forms, uses, and differences between AM and PM is an essential step in developing your mathematical skills. Not only do these concepts help in setting alarms and scheduling activities, but they also enhance your understanding of the broader world, given their international variations. At Brighterly, we believe in turning every moment into a learning opportunity. As we move through our days, divided by these terms of AM and PM, we’re reminded of the beauty of learning – it’s an ongoing process, just like time itself. Keep exploring, keep learning, and remember that every tick and tock is a chance to learn something new!

Frequently Asked Questions on AM and PM

What is the full form of AM?

AM stands for “Ante Meridiem,” a Latin phrase meaning “before midday.” It represents the time period from midnight (12:00 AM) to just before noon (11:59 AM).

What does PM stand for?

PM is an abbreviation for “Post Meridiem,” which translates to “after midday” from Latin. It signifies the time period starting at noon (12:00 PM) and ending just before midnight (11:59 PM).

What is the difference between AM and PM?

The primary difference between AM and PM lies in the time of day they represent. AM corresponds to the hours from midnight to just before noon. On the other hand, PM denotes the time span from noon to just before midnight.

How do I convert time from AM to PM and vice versa?

The conversion between AM and PM is based on the 24-hour day. If the time is given in PM and is greater than 12, subtract 12 to convert it to the AM equivalent for the following day. For instance, 15:00 hours (3:00 PM) would be 3:00 hours (3:00 AM) on the following day. Similarly, if the time is given in AM and you want the PM equivalent for the previous day, add 12 to it. For example, 3:00 hours (3:00 AM) would be 15:00 hours (3:00 PM) on the previous day.

Information Sources
  1. Timekeeping on Wikipedia
  2. National Institute of Standards and Technology
  3. Time and Date
  4. BBC Bitesize

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